Android基础学习（10）-Activity的生命周期
一、Activity的生命周期：
示例1：
Main.java
package com.wwtiot.ozee3;
import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class Main extends Activity {
private Button btnDial, btnPage2, btnFinish;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// 获取资源文件中的界面组件
btnDial = (Button) findViewById(R.id.btnDial);
btnPage2 = (Button) findViewById(R.id.btnPage2);
btnFinish = (Button) findViewById(R.id.btnFinish);
// 为3个按钮组件设置共享listener
btnDial.setOnClickListener(myListener);
btnPage2.setOnClickListener(myListener);
btnFinish.setOnClickListener(myListener);
Toast.makeText(getApplicationContext(), "执行onCreate(1)",
Toast.LENGTH_SHORT).show();
}
private Button.OnClickListener myListener = new Button.OnClickListener() {
@Override
public void onClick(View v) {
if (v.getId() == R.id.btnFinish) {
finish();
} else if (v.getId() == R.id.btnPage2) {
Intent intent = new Intent();
intent.setClass(getApplicationContext(), Second.class);
startActivity(intent);
} else if (v.getId() == R.id.btnDial) {
Uri uri = Uri.parse("tel:1234567");
Intent intent = new Intent(Intent.ACTION_DIAL, uri);
startActivity(intent);
}
}
};
@Override
protected void onStart() {
super.onStart();
Toast.makeText(getApplicationContext(), "执行onStart(1)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onResume() {
super.onResume();
Toast.makeText(getApplicationContext(), "执行onResume(1)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onRestart() {
super.onRestart();
Toast.makeText(getApplicationContext(), "执行onRestart(1)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onPause() {
super.onPause();
Toast.makeText(getApplicationContext(), "执行onPause(1)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onStop() {
super.onStop();
Toast.makeText(getApplicationContext(), "执行onStop(1)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onDestroy() {
super.onDestroy();
Toast.makeText(getApplicationContext(), "执行onDestroy(1)",
Toast.LENGTH_SHORT).show();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".Main" > <Button android:id="@+id/btnDial" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="调用拨号按钮" /> <Button android:id="@+id/btnPage2" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="启动另一个自定义的Activity" /> <Button android:id="@+id/btnFinish" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="finish()结束" /> </LinearLayout>
Second.java
package com.wwtiot.ozee3;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
public class Second extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
Button btnHome = (Button) findViewById(R.id.btnHome);
btnHome.setOnClickListener(myListener);
Toast.makeText(getApplicationContext(), "执行onCreate(2)",
Toast.LENGTH_SHORT).show();
}
private Button.OnClickListener myListener = new Button.OnClickListener() {
@Override
public void onClick(View v) {
finish();
}
};
@Override
protected void onStart() {
super.onStart();
Toast.makeText(getApplicationContext(), "执行onStart(2)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onResume() {
super.onResume();
Toast.makeText(getApplicationContext(), "执行onResume(2)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onRestart() {
super.onRestart();
Toast.makeText(getApplicationContext(), "执行onRestart(2)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onPause() {
super.onPause();
Toast.makeText(getApplicationContext(), "执行onPause(2)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onStop() {
super.onStop();
Toast.makeText(getApplicationContext(), "执行onStop(2)",
Toast.LENGTH_SHORT).show();
}
@Override
protected void onDestroy() {
super.onDestroy();
Toast.makeText(getApplicationContext(), "执行onDestroy(2)",
Toast.LENGTH_SHORT).show();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.second, menu);
return true;
}
}
second.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:orientation="vertical" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".Second" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="第二个程序！" /> <Button android:id="@+id/btnHome" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="返回主程序" /> </LinearLayout>
示例2：
Main.java
package com.wwtiot.ozee4;
import android.media.MediaPlayer;
import android.os.Bundle;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
public class Main extends Activity {
public MediaPlayer player = new MediaPlayer();
private Button btnPause, btnContinue;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
player = MediaPlayer.create(getApplicationContext(), R.raw.moon_night);
// 连续播放
player.setLooping(true);
// 音乐播放
player.start();
// 获取资源文件中的界面组件
btnPause = (Button) findViewById(R.id.btnPause);
btnContinue = (Button) findViewById(R.id.btnContinue);
// 为Button组件设置共享listener
btnPause.setOnClickListener(myListener);
btnContinue.setOnClickListener(myListener);
}
private Button.OnClickListener myListener = new Button.OnClickListener() {
@Override
public void onClick(View v) {
if (v.getId() == R.id.btnPause) {
player.pause();
}
if (v.getId() == R.id.btnContinue) {
player.start();
}
}
};
// 音乐播放暂停
// @Override
// protected void onPause() {
// super.onPause();
// player.pause();
// }
// 音乐继续播放
// @Override
// protected void onResume() {
// super.onResume();
// player.start();
// }
// 释放
// @Override
// protected void onDestroy() {
// super.onDestroy();
// player.release();
// }
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".Main" > <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="@string/hello_world" /> <Button android:id="@+id/btnPause" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="暂停" /> <Button android:id="@+id/btnContinue" android:layout_width="fill_parent" android:layout_height="wrap_content" android:text="播放" /> </LinearLayout>