activity启动模式之singletask模式-优快云博客

本文深入探讨了Android应用间通过Intent启动另一个应用的activity，并详细解释了singletask模式下活动启动与任务切换的原理及实现方式。通过应用实例展示了如何使用Intent和singletask模式来控制活动加载和任务行为。

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其他应用启动另外一个应用的activity：

方法一

	Intent intent = new Intent();
				intent.setAction("sec");
				intent.setComponent(new ComponentName("com.test","com.test.SecActivity"));   
			    startActivity(intent);

方法二

activity启动模式之singletask细说：

两种情况：（activity A假设是singletask模式，它在应用1中定义）

1 如果应用1想启动 A ，则 A 不会新建task，而是加载到应用1的task中。另外如果 A 启动了其他的activity，则这个activity会加载在 A 的上面，如果A再次被启动，则 A上面的所有activity实例被销毁。

2 如果应用2要启动 A ，则 A 在新的task或则在应用1的task中加载。

测试代码如下：

应用1 ：

package com.test;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class TestTaskActivity extends Activity implements OnClickListener{
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        Log.d("11111", "activity1  "+getTaskId());
       
        Button button = (Button) findViewById(R.id.button1);
		button.setOnClickListener(this);
    }
    
    @Override
	public void onClick(View v) {
		Intent intent  = new Intent(this, SecActivity.class);
		startActivity(intent);
	}
    
    @Override
	public void onBackPressed() {
		// TODO Auto-generated method stub
//		super.onBackPressed();
		Log.d("1111111", "back");
		finish();
	}
}

下面这个activity是singletask

package com.test;

import android.app.Activity;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class SecActivity extends Activity implements OnClickListener{

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.layout2);
		Log.d("2222", "activity2 oncreat "+ getTaskId());
		Button button = (Button) findViewById(R.id.button1);
		button.setOnClickListener(this);
		IntentFilter mFilter = new IntentFilter("sec");
		registerReceiver(mReceiver, mFilter);
	}

	@Override
	protected void onNewIntent(Intent intent) {
		super.onNewIntent(intent);
		Log.d("2222", "activity2 onNewIntent "+ getTaskId());
	}

	@Override
	public void onClick(View v) {
		Intent intent  = new Intent(this, ThirdActivity.class);
		startActivity(intent);
	}

	@Override
	public void onBackPressed() {
		// TODO Auto-generated method stub
//		super.onBackPressed();
		Log.d("2222222", "back");
		finish();
		unregisterReceiver(mReceiver);
	}
	
	private BroadcastReceiver mReceiver = new   MyBroadcastReceiver();
		
	public class MyBroadcastReceiver extends BroadcastReceiver {
		
		@Override
		public void onReceive(Context context, Intent intent) {
			// TODO Auto-generated method stub
			Log.d("2222222", "receive intent");
		}
	}
	
}

package com.test;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class ThirdActivity extends Activity implements OnClickListener{
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.layout3);
		Log.d("333333", "activity3 oncreat "+ getTaskId());
		Button button = (Button) findViewById(R.id.button1);
		button.setOnClickListener(this);
	}

	@Override
	protected void onNewIntent(Intent intent) {
		super.onNewIntent(intent);
		Log.d("333333", "activity3 onNewIntent "+ getTaskId());
	}

	@Override
	public void onClick(View v) {
		Intent intent  = new Intent(this, SecActivity.class);
		startActivity(intent);
	}

	/* (non-Javadoc)
	 * @see android.app.Activity#onBackPressed()
	 */
	@Override
	public void onBackPressed() {
		// TODO Auto-generated method stub
//		super.onBackPressed();
		Log.d("333333", "back");
		finish();
	}


}

应用2的代码：

package com.test1;

import android.app.Activity;
import android.content.ComponentName;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;

import com.test1.*;

public class TestSingleTaskActivity extends Activity {
    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        findViewById(R.id.button1).setOnClickListener(new OnClickListener() {
			
			@Override
			public void onClick(View v) {
				Log.d("aaaaaaa", "taskid  "+ getTaskId());
				// TODO Auto-generated method stub
//				Intent  intent= new Intent(TestSingleTaskActivity.this, SecActivity.class);
				Intent intent = new Intent();
				intent.setAction("sec");
				intent.setComponent(new ComponentName("com.test","com.test.SecActivity"));   
			    startActivity(intent);   
//				sendBroadcast(intent);
			}
		});
    }
}