In Android , Content Providers are a very important component that serves the purpose of a relational database to store the data of applications. The role of the content provider in the android system is like a central repository in which data of the applications are stored, and it facilitates other applications to securely access and modifies that data based on the user requirements. Android system allows the content provider to store the application data in several ways. Users can manage to store the application data like images, audio, videos, and personal contact information by storing them in SQLite Database , in files , or even on a network . In order to share the data, content providers have certain permissions that are used to grant or restrict the rights to other applications to interfere with the data.
Content URI
Content URI(Uniform Resource Identifier) is the key concept of Content providers. To access the data from a content provider, URI is used as a query string.
Structure of a Content URI: content://authority/optionalPath/optionalID
Details of different parts of Content URI:
- content:// - Mandatory part of the URI as it represents that the given URI is a Content URI.
- authority - Signifies the name of the content provider like contacts, browser, etc. This part must be unique for every content provider.
- optionalPath - Specifies the type of data provided by the content provider. It is essential as this part helps content providers to support different types of data that are not related to each other like audio and video files.
- optionalID - It is a numeric value that is used when there is a need to access a particular record.
If an ID is mentioned in a URI then it is an id-based URI otherwise a directory-based URI.
Operations in Content Provider
Four fundamental operations are possible in Content Provider namely Create , Read , Update , and Delete . These operations are often termed as CRUD operations .
- Create: Operation to create data in a content provider.
- Read: Used to fetch data from a content provider.
- Update: To modify existing data.
- Delete: To remove existing data from the storage.
Working of the Content Provider
UI components of android applications like Activity and Fragments use an object CursorLoader to send query requests to ContentResolver. The ContentResolver object sends requests (like create, read, update, and delete) to the ContentProvider as a client. After receiving a request, ContentProvider process it and returns the desired result. Below is a diagram to represent these processes in pictorial form.
Creating a Content Provider
Following are the steps which are essential to follow in order to create a Content Provider:
- Create a class in the same directory where the that MainActivity file resides and this class must extend the ContentProvider base class.
- To access the content, define a content provider URI address.
- Create a database to store the application data.
- Implement the six abstract methods of ContentProvider class.
- Register the content provider in AndroidManifest.xml file using <provider> tag .
Following are the six abstract methods and their description which are essential to override as the part of ContenProvider class:
Abstract Method | Description |
|---|---|
| query() | A method that accepts arguments and fetches the data from the desired table. Data is retired as a cursor object. |
| insert() | To insert a new row in the database of the content provider. It returns the content URI of the inserted row. |
| update() | This method is used to update the fields of an existing row. It returns the number of rows updated. |
| delete() | This method is used to delete the existing rows. It returns the number of rows deleted. |
| getType() | This method returns the Multipurpose Internet Mail Extension(MIME) type of data to the given Content URI. |
| onCreate() | As the content provider is created, the android system calls this method immediately to initialise the provider. |
Example
The prime purpose of a content provider is to serve as a central repository of data where users can store and can fetch the data. The access of this repository is given to other applications also but in a safe manner in order to serve the different requirements of the user. The following are the steps involved in implementing a content provider. In this content provider, the user can store the name of persons and can fetch the stored data. Moreover, another application can also access the stored data and can display the data.
Note: Following steps are performed on Android Studio version 4.0
Creating a Content Provider:
Step 1: Create a new project
- Click on File, then New => New Project.
- Select language as Java/Kotlin.
- Choose empty activity as a template
- Select the minimum SDK as per your need.
Step 2: Modify the strings.xml file
All the strings used in the activity are stored here.
<resources>
<string name="app_name">Content_Provider_In_Android</string>
<string name="hintText">Enter User Name</string>
<string name="heading">Content Provider In Android</string>
<string name="insertButtontext">Insert Data</string>
<string name="loadButtonText">Load Data</string>
</resources>
Step 3: Creating the Content Provider class
- Click on File, then New => Other => ContentProvider.
- Name the ContentProvider
- Define authority (it can be anything for example "com.demo.user.provider" )
- Select Exported and Enabled option
- Choose the language as Java/Kotlin
This class extends the ContentProvider base class and override the six abstract methods. Below is the complete code to define a content provider.
package com.example.contentprovidersinandroid;
import android.content.ContentProvider;
import android.content.ContentUris;
import android.content.ContentValues;
import android.content.Context;
import android.content.UriMatcher;
import android.database.Cursor;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;
import android.database.sqlite.SQLiteQueryBuilder;
import android.net.Uri;
import java.util.HashMap;
public class MyContentProvider extends ContentProvider {
public MyContentProvider() {
}
// defining authority so that other application can access it
static final String PROVIDER_NAME = "com.demo.user.provider";
// defining content URI
static final String URL = "content://" + PROVIDER_NAME + "/users";
// parsing the content URI
static final Uri CONTENT_URI = Uri.parse(URL);
static final String id = "id";
static final String name = "name";
static final int uriCode = 1;
static final UriMatcher uriMatcher;
private static HashMap<String, String> values;
static {
// to match the content URI
// every time user access table under content provider
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
// to access whole table
uriMatcher.addURI(PROVIDER_NAME, "users", uriCode);
// to access a particular row
// of the table
uriMatcher.addURI(PROVIDER_NAME, "users/*", uriCode);
}
@Override
public String getType(Uri uri) {
switch (uriMatcher.match(uri)) {
case uriCode:
return "vnd.android.cursor.dir/users";
default:
throw new IllegalArgumentException("Unsupported URI: " + uri);
}
}
// creating the database
@Override
public boolean onCreate() {
Context context = getContext();
DatabaseHelper dbHelper = new DatabaseHelper(context);
db = dbHelper.getWritableDatabase();
if (db != null) {
return true;
}
return false;
}
@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {
SQLiteQueryBuilder qb = new SQLiteQueryBuilder();
qb.setTables(TABLE_NAME);
switch (uriMatcher.match(uri)) {
case uriCode:
qb.setProjectionMap(values);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
if (sortOrder == null || sortOrder == "") {
sortOrder = id;
}
Cursor c = qb.query(db, projection, selection, selectionArgs, null,
null, sortOrder);
c.setNotificationUri(getContext().getContentResolver(), uri);
return c;
}
// adding data to the database
@Override
public Uri insert(Uri uri, ContentValues values) {
long rowID = db.insert(TABLE_NAME, "", values);
if (rowID > 0) {
Uri _uri = ContentUris.withAppendedId(CONTENT_URI, rowID);
getContext().getContentResolver().notifyChange(_uri, null);
return _uri;
}
throw new SQLiteException("Failed to add a record into " + uri);
}
@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {
int count = 0;
switch (uriMatcher.match(uri)) {
case uriCode:
count = db.update(TABLE_NAME, values, selection, selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {
int count = 0;
switch (uriMatcher.match(uri)) {
case uriCode:
count = db.delete(TABLE_NAME, selection, selectionArgs);
break;
default:
throw new IllegalArgumentException("Unknown URI " + uri);
}
getContext().getContentResolver().notifyChange(uri, null);
return count;
}
// creating object of database
// to perform query
private SQLiteDatabase db;
// declaring name of the database
static final String DATABASE_NAME = "UserDB";
// declaring table name of the database
static final String TABLE_NAME = "Users";
// declaring version of the database
static final int DATABASE_VERSION = 1;
// sql query to create the table
static final String CREATE_DB_TABLE = " CREATE TABLE " + TABLE_NAME
+ " (id INTEGER PRIMARY KEY AUTOINCREMENT, "
+ " name TEXT NOT NULL);";
// creating a database
private static class DatabaseHelper extends SQLiteOpenHelper {
// defining a constructor
DatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
// creating a table in the database
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL(CREATE_DB_TABLE);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
// sql query to drop a table
// having similar name
db.execSQL("DROP TABLE IF EXISTS " + TABLE_NAME);
onCreate(db);
}
}
}
package com.example.contentprovidersinandroid
import android.content.*
import android.database.Cursor
import android.database.sqlite.SQLiteDatabase
import android.database.sqlite.SQLiteException
import android.database.sqlite.SQLiteOpenHelper
import android.database.sqlite.SQLiteQueryBuilder
import android.net.Uri
class MyContentProvider : ContentProvider() {
companion object {
// defining authority so that other application can access it
const val PROVIDER_NAME = "com.demo.user.provider"
// defining content URI
const val URL = "content://$PROVIDER_NAME/users"
// parsing the content URI
val CONTENT_URI = Uri.parse(URL)
const val id = "id"
const val name = "name"
const val uriCode = 1
var uriMatcher: UriMatcher? = null
private val values: HashMap<String, String>? = null
// declaring name of the database
const val DATABASE_NAME = "UserDB"
// declaring table name of the database
const val TABLE_NAME = "Users"
// declaring version of the database
const val DATABASE_VERSION = 1
// sql query to create the table
const val CREATE_DB_TABLE =
(" CREATE TABLE " + TABLE_NAME
+ " (id INTEGER PRIMARY KEY AUTOINCREMENT, "
+ " name TEXT NOT NULL);")
init {
// to match the content URI
// every time user access table under content provider
uriMatcher = UriMatcher(UriMatcher.NO_MATCH)
// to access whole table
uriMatcher!!.addURI(
PROVIDER_NAME,
"users",
uriCode
)
// to access a particular row
// of the table
uriMatcher!!.addURI(
PROVIDER_NAME,
"users/*",
uriCode
)
}
}
override fun getType(uri: Uri): String? {
return when (uriMatcher!!.match(uri)) {
uriCode -> "vnd.android.cursor.dir/users"
else -> throw IllegalArgumentException("Unsupported URI: $uri")
}
}
// creating the database
override fun onCreate(): Boolean {
val context = context
val dbHelper =
DatabaseHelper(context)
db = dbHelper.writableDatabase
return if (db != null) {
true
} else false
}
override fun query(
uri: Uri, projection: Array<String>?, selection: String?,
selectionArgs: Array<String>?, sortOrder: String?
): Cursor? {
var sortOrder = sortOrder
val qb = SQLiteQueryBuilder()
qb.tables = TABLE_NAME
when (uriMatcher!!.match(uri)) {
uriCode -> qb.projectionMap = values
else -> throw IllegalArgumentException("Unknown URI $uri")
}
if (sortOrder == null || sortOrder === "") {
sortOrder = id
}
val c = qb.query(
db, projection, selection, selectionArgs, null,
null, sortOrder
)
c.setNotificationUri(context!!.contentResolver, uri)
return c
}
// adding data to the database
override fun insert(uri: Uri, values: ContentValues?): Uri? {
val rowID = db!!.insert(TABLE_NAME, "", values)
if (rowID > 0) {
val _uri =
ContentUris.withAppendedId(CONTENT_URI, rowID)
context!!.contentResolver.notifyChange(_uri, null)
return _uri
}
throw SQLiteException("Failed to add a record into $uri")
}
override fun update(
uri: Uri, values: ContentValues?, selection: String?,
selectionArgs: Array<String>?
): Int {
var count = 0
count = when (uriMatcher!!.match(uri)) {
uriCode -> db!!.update(TABLE_NAME, values, selection, selectionArgs)
else -> throw IllegalArgumentException("Unknown URI $uri")
}
context!!.contentResolver.notifyChange(uri, null)
return count
}
override fun delete(
uri: Uri,
selection: String?,
selectionArgs: Array<String>?
): Int {
var count = 0
count = when (uriMatcher!!.match(uri)) {
uriCode -> db!!.delete(TABLE_NAME, selection, selectionArgs)
else -> throw IllegalArgumentException("Unknown URI $uri")
}
context!!.contentResolver.notifyChange(uri, null)
return count
}
// creating object of database
// to perform query
private var db: SQLiteDatabase? = null
// creating a database
private class DatabaseHelper // defining a constructor
internal constructor(context: Context?) : SQLiteOpenHelper(
context,
DATABASE_NAME,
null,
DATABASE_VERSION
) {
// creating a table in the database
override fun onCreate(db: SQLiteDatabase) {
db.execSQL(CREATE_DB_TABLE)
}
override fun onUpgrade(
db: SQLiteDatabase,
oldVersion: Int,
newVersion: Int
) {
// sql query to drop a table
// having similar name
db.execSQL("DROP TABLE IF EXISTS $TABLE_NAME")
onCreate(db)
}
}
}
Step 4: Design the activity_main.xml layout
One Textview , EditText field, two Buttons , and a Textview to display the stored data will be added in the activity using the below code.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#168BC34A"
tools:context=".MainActivity">
<LinearLayout
android:id="@+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:orientation="vertical"
app:layout_constraintBottom_toTopOf="@+id/imageView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.13"
tools:ignore="MissingConstraints">
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="40dp"
android:layout_marginBottom="70dp"
android:fontFamily="@font/roboto"
android:text="@string/heading"
android:textAlignment="center"
android:textAppearance="@style/TextAppearance.AppCompat.Large"
android:textColor="@android:color/holo_green_dark"
android:textSize="36sp"
android:textStyle="bold" />
<EditText
android:id="@+id/textName"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginEnd="20dp"
android:layout_marginBottom="40dp"
android:fontFamily="@font/roboto"
android:hint="@string/hintText" />
<Button
android:id="@+id/insertButton"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginStart="20dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="20dp"
android:layout_marginBottom="20dp"
android:background="#4CAF50"
android:fontFamily="@font/roboto"
android:onClick="onClickAddDetails"
android:text="@string/insertButtontext"
android:textAlignment="center"
android:textAppearance="@style/TextAppearance.AppCompat.Display1"
android:textColor="#FFFFFF"
android:textStyle="bold" />
<Button
android:id="@+id/loadButton"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginStart="20dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="20dp"
android:layout_marginBottom="20dp"
android:background="#4CAF50"
android:fontFamily="@font/roboto"
android:onClick="onClickShowDetails"
android:text="@string/loadButtonText"
android:textAlignment="center"
android:textAppearance="@style/TextAppearance.AppCompat.Display1"
android:textColor="#FFFFFF"
android:textStyle="bold" />
<TextView
android:id="@+id/res"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginEnd="20dp"
android:clickable="false"
android:ems="10"
android:fontFamily="@font/roboto"
android:textColor="@android:color/holo_green_dark"
android:textSize="18sp"
android:textStyle="bold" />
</LinearLayout>
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:srcCompat="@drawable/banner" />
</androidx.constraintlayout.widget.ConstraintLayout>
Step 5: Modify the MainActivity file
Button functionalities will be defined in this file. Moreover, the query to be performed while inserting and fetching the data is mentioned here. Below is the complete code.
package com.example.contentprovidersinandroid;
import androidx.appcompat.app.AppCompatActivity;
import android.content.ContentValues;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.MotionEvent;
import android.view.View;
import android.view.inputmethod.InputMethodManager;
import android.widget.EditText;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
@Override
public boolean onTouchEvent(MotionEvent event) {
InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(getCurrentFocus().getWindowToken(), 0);
return true;
}
public void onClickAddDetails(View view) {
// class to add values in the database
ContentValues values = new ContentValues();
// fetching text from user
values.put(MyContentProvider.name, ((EditText) findViewById(R.id.textName)).getText().toString());
// inserting into database through content URI
getContentResolver().insert(MyContentProvider.CONTENT_URI, values);
// displaying a toast message
Toast.makeText(getBaseContext(), "New Record Inserted", Toast.LENGTH_LONG).show();
}
public void onClickShowDetails(View view) {
// inserting complete table details in this text field
TextView resultView= (TextView) findViewById(R.id.res);
// creating a cursor object of the
// content URI
Cursor cursor = getContentResolver().query(Uri.parse("content://com.demo.user.provider/users"), null, null, null, null);
// iteration of the cursor
// to print whole table
if(cursor.moveToFirst()) {
StringBuilder strBuild=new StringBuilder();
while (!cursor.isAfterLast()) {
strBuild.append("\n"+cursor.getString(cursor.getColumnIndex("id"))+ "-"+ cursor.getString(cursor.getColumnIndex("name")));
cursor.moveToNext();
}
resultView.setText(strBuild);
}
else {
resultView.setText("No Records Found");
}
}
}
package com.example.content_provider_in_android
import android.content.ContentValues
import android.content.Context
import android.net.Uri
import android.os.Bundle
import android.view.MotionEvent
import android.view.View
import android.view.inputmethod.InputMethodManager
import android.widget.EditText
import android.widget.TextView
import android.widget.Toast
import androidx.appcompat.app.AppCompatActivity
import com.example.contentprovidersinandroid.MyContentProvider
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}
override fun onTouchEvent(event: MotionEvent?): Boolean {
val imm = getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
imm.hideSoftInputFromWindow(currentFocus!!.windowToken, 0)
return true
}
fun onClickAddDetails(view: View?) {
// class to add values in the database
val values = ContentValues()
// fetching text from user
values.put(MyContentProvider.name, (findViewById<View>(R.id.textName) as EditText).text.toString())
// inserting into database through content URI
contentResolver.insert(MyContentProvider.CONTENT_URI, values)
// displaying a toast message
Toast.makeText(baseContext, "New Record Inserted", Toast.LENGTH_LONG).show()
}
fun onClickShowDetails(view: View?) {
// inserting complete table details in this text field
val resultView = findViewById<View>(R.id.res) as TextView
// creating a cursor object of the
// content URI
val cursor = contentResolver.query(Uri.parse("content://com.demo.user.provider/users"), null, null, null, null)
// iteration of the cursor
// to print whole table
if (cursor!!.moveToFirst()) {
val strBuild = StringBuilder()
while (!cursor.isAfterLast) {
strBuild.append("""
${cursor.getString(cursor.getColumnIndex("id"))}-${cursor.getString(cursor.getColumnIndex("name"))}
""".trimIndent())
cursor.moveToNext()
}
resultView.text = strBuild
} else {
resultView.text = "No Records Found"
}
}
}
Step 6: Modify the AndroidManifest file
The AndroidManifest file must contain the content provider name, authorities, and permissions which enable the content provider to be accessed by other applications.
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.content_provider_in_android">
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:roundIcon="@mipmap/ic_launcher_round"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<provider
android:name="com.example.contentprovidersinandroid.MyContentProvider"
android:authorities="com.demo.user.provider"
android:enabled="true"
android:exported="true"></provider>
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
<meta-data
android:name="preloaded_fonts"
android:resource="@array/preloaded_fonts" />
</application>
</manifest>
Creating another application to access the Content Provider:
Step 1: Create a new Project
- Click on File, then New => New Project.
- Select language as Java/Kotlin.
- Choose empty activity as a template
- Select the minimum SDK as per your need.
Step 2: Modify strings.xml file
All the strings used in the activity are stored in this file.
<resources>
<string name="app_name">Accessing_Content_Provider</string>
<string name="heading">Accessing data of Content Provider</string>
<string name="loadButtonText">Load Data</string>
</resources>
Step 3: Designing the activity_main.xml layout
Two TextView are added in the activity, one for heading and one to display the stored data in a content provider. One Button is also added to receive the command to display data. Below is the code to implement this design.
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#168BC34A"
tools:context=".MainActivity">
<LinearLayout
android:id="@+id/linearLayout"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:orientation="vertical"
app:layout_constraintBottom_toTopOf="@+id/imageView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.13"
tools:ignore="MissingConstraints">
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginTop="40dp"
android:layout_marginBottom="70dp"
android:fontFamily="@font/roboto"
android:text="@string/heading"
android:textAlignment="center"
android:textAppearance="@style/TextAppearance.AppCompat.Large"
android:textColor="@android:color/holo_green_dark"
android:textSize="36sp"
android:textStyle="bold" />
<Button
android:id="@+id/loadButton"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_marginStart="20dp"
android:layout_marginTop="10dp"
android:layout_marginEnd="20dp"
android:layout_marginBottom="20dp"
android:background="#4CAF50"
android:fontFamily="@font/roboto"
android:onClick="onClickShowDetails"
android:text="@string/loadButtonText"
android:textAlignment="center"
android:textAppearance="@style/TextAppearance.AppCompat.Display1"
android:textColor="#FFFFFF"
android:textStyle="bold" />
<TextView
android:id="@+id/res"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_marginStart="20dp"
android:layout_marginEnd="20dp"
android:clickable="false"
android:ems="10"
android:fontFamily="@font/roboto"
android:textColor="@android:color/holo_green_dark"
android:textSize="18sp"
android:textStyle="bold" />
</LinearLayout>
<ImageView
android:id="@+id/imageView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:srcCompat="@drawable/banner" />
</androidx.constraintlayout.widget.ConstraintLayout>
Step 4: Modify the MainActivity file
The ContentURI of the previous application is mentioned here and the same functions which were used in the previous app to display the records will also be used here. Below is the complete code:
package com.example.accessingcontentprovider;
import androidx.appcompat.app.AppCompatActivity;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class MainActivity extends AppCompatActivity {
Uri CONTENT_URI = Uri.parse("content://com.demo.user.provider/users");
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
}
public void onClickShowDetails(View view) {
// inserting complete table details in this text field
TextView resultView= (TextView) findViewById(R.id.res);
// creating a cursor object of the
// content URI
Cursor cursor = getContentResolver().query(Uri.parse("content://com.demo.user.provider/users"), null, null, null, null);
// iteration of the cursor
// to print whole table
if(cursor.moveToFirst()) {
StringBuilder strBuild=new StringBuilder();
while (!cursor.isAfterLast()) {
strBuild.append("\n"+cursor.getString(cursor.getColumnIndex("id"))+ "-"+ cursor.getString(cursor.getColumnIndex("name")));
cursor.moveToNext();
}
resultView.setText(strBuild);
}
else {
resultView.setText("No Records Found");
}
}
}
package com.example.accessing_content_provider
import android.net.Uri
import android.os.Bundle
import android.view.View
import android.widget.TextView
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
var CONTENT_URI = Uri.parse("content://com.demo.user.provider/users")
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
}
fun onClickShowDetails(view: View?) {
// inserting complete table details in this text field
val resultView = findViewById<View>(R.id.res) as TextView
// creating a cursor object of the
// content URI
val cursor = contentResolver.query(Uri.parse("content://com.demo.user.provider/users"), null, null, null, null)
// iteration of the cursor
// to print whole table
if (cursor!!.moveToFirst()) {
val strBuild = StringBuilder()
while (!cursor.isAfterLast) {
strBuild.append("""
${cursor.getString(cursor.getColumnIndex("id"))}-${cursor.getString(cursor.getColumnIndex("name"))}
""".trimIndent())
cursor.moveToNext()
}
resultView.text = strBuild
} else {
resultView.text = "No Records Found"
}
}
}
Output: Run on Emulator
Step 5: Modify the AndroidManifest.xml file
Don't forget to add <query> permission (API 30 and above).
For more details refer here .
<queries>
<package android:name="com.example.contentprovidersinandroid"/>
</queries>
<application>
.
.
.
</application>