演示Activity的生命周期

来源：互联网发布：华为软件研发面试经验编辑：程序博客网时间：2024/05/17 03:48

Activity的生命周期：

演示过程：（1）MainActivity和Activity2之间的代码

Activity2的代码：

package com.example.mactivitytest;
import android.app.Activity;
import android.app.ActionBar;
import android.app.Fragment;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.os.Build;

public class MainActivity extends Activity {
private Button btn1,btn2;
//Activity创建时被调用
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.fragment_main);
Log.d("MainActivity", "onCreate");
btn1=(Button) findViewById(R.id.btn1);
btn2=(Button) findViewById(R.id.btn2);
btn1.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent=new Intent(getApplicationContext(),Activity2.class);
startActivity(intent);
// MainActivity.this.finish();
}
});
btn2.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
MainActivity.this.finish();
}
});

}
//Activity创建或者从后台重新回到前台时被调用
@Override
protected void onStart() {
// TODO Auto-generated method stub
super.onStart();
Log.d("MainActivity", "onStart");

}
//Activity创建或者从被覆盖、后台重新回到前台时被调用
@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
Log.d("MainActivity", "onResume");
}
//Activity被覆盖到下面或者锁屏时被调用
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
Log.d("MainActivity", "onPause");
}
//退出当前Activity或者跳转到新Activity时被调用
@Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
Log.d("MainActivity", "onStop");

}
//退出当前Activity时被调用,调用之后Activity就结束了
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
Log.d("MainActivity", "onDestroy");
}
}

mainActivity的代码：

package com.example.mactivitytest;
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 Activity2 extends Activity {
private Button btn3, btn4;

@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Log.d("Activity2", "onCreate");
btn3=(Button) findViewById(R.id.btn3);
btn4=(Button) findViewById(R.id.btn4);
btn3.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Intent intent = new Intent(getApplicationContext(), MainActivity.class);
startActivity(intent);
// Activity2.this.finish();
}
});
btn4.setOnClickListener(new OnClickListener() {

@Override
public void onClick(View v) {
// TODO Auto-generated method stub
Activity2.this.finish();
}
});

}

@Override
protected void onStart() {
// TODO Auto-generated method stub
super.onStart();
Log.d("Activity2", "onStart");

}

@Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
Log.d("Activity2", "onResume");
}

@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
Log.d("Activity2", "onPause");
}
@Override
protected void onStop() {
// TODO Auto-generated method stub
super.onStop();
Log.d("Activity2", "onStop");

}
@Override
protected void onDestroy() {
// TODO Auto-generated method stub
super.onDestroy();
Log.d("Activity2", "onDestroy");
}
}

布局activity_main：<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:orientation="vertical" >

<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="@string/test2" />

<Button
android:id="@+id/btn3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="切换到第二个activity" />

<Button
android:id="@+id/btn4"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="关闭" />

</LinearLayout>

布局fragment_main:

演示效果：（1）运行项目

在系统调用了onCreate和onStart之后，调用了onResume，自此，Activity进入了运行状态。

（2）点击切换到第一个Activity按钮

在启动Activity2调用Activity2的oncreate,onstart,oonResume.让MainACtivity处于onstop状态中。

（3）点击切换到第二个Activity按钮

调用Activity2的onpause.重新调用MainActivity的oncreate,onstaart,onResume.让Activity处于onstop的状态中。

我就演示到这。其他点击可以自由组合，观察生命周期。

mActivityTest源码链接：http://pan.baidu.com/s/1kVua3xd

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