How to Pass Data from One Activity to Another in Android

សេង ស៊ង់

21 Jul, 2022

នៅក្នុងមេរៀននេះ អ្នកនឹងរៀនបញ្ជូនទិន្នន័យពីសកម្មភាព(activity )មួយទៅសកម្មភាព(activity )មួយទៀតនៅក្នុងប្រព័ន្ធប្រតិបត្តិការ Android ដោយមិនប្រើ intent។

Basically we can send data between activities in two ways.

Using Intent
Using Global Variables

Below I have discussed both the methods in detail.

Note: There are some other ways like shared preferences and database (sqlite) but here I have shared only those ways that don’t involve saving of data.

Method 1: Using Intent

We can send data while calling one activity from another activity using intent. All we have to do is add the data to Intent object using putExtra() method. The data is passed in key value pair. The value can be of types like int, float, long, string, etc.

Sending Data

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Intent intent = new Intent(context, DestinationActivityName.class);
intent.putExtra(Key, Value);
startActivity(intent);

Here I am sending just one value, in the same way you can attach more values by using putExtra() method.

Retrieving Data

If the data sent is of type string then it can be fetched in following way.

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Intent intent = getIntent();
String str = intent.getStringExtra(Key);

There are several other methods like getIntExtra(), getFloatExtra(), etc to fetch other types of data.

Below is the example of passing data between activities using intents.

Example

In this example a message is passed from first activity to second when a button is pressed.

activity_first.xml

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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="15dp"
    tools:context="com.androidexample.First"
    android:orientation="vertical">
 
    <EditText
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/textBox"
        android:hint="Enter Your Message"/>
 
    <Button
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:id="@+id/passButton"
        android:text="Pass"/>
</LinearLayout>

activity_second.xml

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<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="15dp"
    tools:context="com.androidexample.Second">
 
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text=""
        android:id="@+id/text"/>
</LinearLayout>

First.java

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package com.androidexample;
 
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
 
public class First extends AppCompatActivity {
    EditText textBox;
    Button passButton;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_first);
 
        textBox = (EditText)findViewById(R.id.textBox);
        passButton = (Button)findViewById(R.id.passButton);
 
        passButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String str = textBox.getText().toString();
 
                Intent intent = new Intent(getApplicationContext(), Second.class);
                intent.putExtra("message", str);
 
                startActivity(intent);
            }
        });
    }
}

Second.java

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package com.androidexample;
 
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
 
public class Second extends AppCompatActivity {
    TextView text;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
 
        text = (TextView)findViewById(R.id.text);
 
        Intent intent = getIntent();
        String str = intent.getStringExtra("message");
        text.setText(str);
    }
}

Screenshots

Method 2: Using Global Variables

We can declare a global variable in a separate class. To make it global just declare it as public static. This will allow us to directly access the variable anywhere in our application using its class name.

Just assign the value that you want to pass in global variable inside source activity and fetch it in destination activity by accessing the global variable.

Below example shows how to do this.

Example

The code for activity_first.xml and activity_second.xml will be same as above example.

DemoClass.java

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package com.androidexample;
 
public class DemoClass {
    public static String message;   //global variable
}

First.java

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package com.androidexample;
 
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
 
public class First extends AppCompatActivity {
    EditText textBox;
    Button passButton;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_first);
 
        textBox = (EditText)findViewById(R.id.textBox);
        passButton = (Button)findViewById(R.id.passButton);
 
        passButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                DemoClass.message = textBox.getText().toString();
 
                Intent intent = new Intent(getApplicationContext(), Second.class);
                startActivity(intent);
            }
        });
    }
}

Second.java

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package com.androidexample;
 
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;
 
public class Second extends AppCompatActivity {
    TextView text;
 
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_second);
 
        text = (TextView)findViewById(R.id.text);
 
        text.setText(DemoClass.message);
    }
}