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Activity生命周期

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首先建立一個android項目, 打開.java文件,只有一個創建生命周期的方法,添加生命周期的其他方法,如下

package com.csdn.Activity;

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import android.app.Activity;

import android.os.Bundle;

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public class LifeCycleActivity extendsActivity {

???/** Called when the activity is first created. */

?????? //創建

???@Override

???public void onCreate(Bundle savedInstanceState) {

???????super.onCreate(savedInstanceState);

???????setContentView(R.layout.main);

???????System.out.println("活動被創建");

??? }

???

???//銷毀

?????? @Override

?????? protectedvoid onDestroy() {

????????????? //TODO Auto-generated method stub

????????????? super.onDestroy();

????????????? System.out.println("活動被摧毀");

?????? }

?????? //暫停

?????? @Override

?????? protectedvoid onPause() {

????????????? //TODO Auto-generated method stub

????????????? super.onPause();

????????????? System.out.println("活動被暫停");

?????? }

?????? //重新開始

?????? @Override

?????? protectedvoid onRestart() {

????????????? //TODO Auto-generated method stub

????????????? super.onRestart();

????????????? System.out.println("活動被重新開始");

?????? }

?????? //重新啟動

?????? @Override

?????? protectedvoid onResume() {

????????????? //TODO Auto-generated method stub

????????????? super.onResume();

????????????? System.out.println("活動被重新啟動");

?????? }

?????? //啟動

?????? @Override

?????? protectedvoid onStart() {

????????????? //TODO Auto-generated method stub

????????????? super.onStart();

????????????? System.out.println("活動被啟動");

?????? }

?????? //停止

?????? @Override

?????? protectedvoid onStop() {

????????????? //TODO Auto-generated method stub

????????????? super.onStop();

????????????? System.out.println("活動被停止");

?????? }

???

}

打開Logcat面板,,添加過濾字符,,建立一個過濾System,out的,,,然后運行項目,,再Logcat

上得出的結果是

虛擬器的界面是

當點擊返回按鈕時,退出后顯示的結果是

活動被銷毀

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電話打入的效果是

當接電話掛斷后的結果是Laycat界面出現的

虛擬器的界面還是運行后的界面,,,,,活動并沒有被銷毀..

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吐司

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打開Layout下的main? 在界面上加一個按鈕,按鈕上的字符串寫為按鈕,按鈕名為strBtn?? ,并把按鈕的Id設為Btn

打開建立好的Activity.java文件? 獲取一下main上的那個按鈕

Button nextBtn = (Button)findViewById(R.id.nextBtn);

然后在按鈕上添加事件

nextBtn.setOnClickListener(newOnClickListener(){

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???????????????????? @Override

???????????????????? publicvoid onClick(View v) {

??????????????????????????? //TODO Auto-generated method stub

??????????????????????????? Toast.makeText(JavaActivity.this,"按鈕",Toast.LENGTH_SHORT).show();

???????????????????? }

?????????????

???????});

當點擊按鈕的時候就會出現吐司,吐司語句

Toast.makeText(JavaActivity.this, "按鈕",Toast.LENGTH_SHORT).show();

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Android界面的切換

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在Layout下建立一個信息的xml文件,,我命名為mains,,,,,在界面上添加一個按鈕,按鈕上的字符串設置為下一個界面,設置ID為nextBtn,,,,保存,,在Acitivity包下再建立一個second.java的文件,,繼承Acitivity,,,,重寫父類的方法,,,,在方法里面加入setContentView(R.layout.mains);

在first.java的文件中獲取main上的按鈕

Button nextBtn = (Button)findViewById(R.id.nextBtn);

?? ?????nextBtn.setOnClickListener(newOnClickListener(){

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???????????????????? @Override

???????????????????? publicvoid onClick(View v) {

??????????????????????????? //TODO Auto-generated method stub

??????????????????????????? Toast.makeText(JavaActivity.this,"下一個界面",Toast.LENGTH_SHORT).show();

???????????????????????????

??????????????????????????? Intentintent=new Intent(JavaActivity.this,Second.class);

??????????????????????????? startActivity(intent);

???????????????????? }

?????????????

???????});

在second.java的文件中獲取mains上的按鈕

Button nextBtn = (Button)findViewById(R.id.backBtn);

?????? ??????? nextBtn.setOnClickListener(newOnClickListener(){

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??????????????????????????? @Override

??????????????????????????? publicvoid onClick(View v) {

?????????????????????????????????? //TODO Auto-generated method stub

?????????????????????????????????? Toast.makeText(Second.this,"上一個界面",Toast.LENGTH_SHORT).show();

??????????????????????????????????

?????????????????????????????????? Intentintent=new Intent(Second.this,JavaActivity.class);

?????????????????????????????????? startActivity(intent);

??????????????????????????? }

?????? ??????? ??????

?????? ??????? });

運行一下該程序,,,就會顯示你設置好的界面的切換…

轉載于:https://www.cnblogs.com/javaTest/archive/2012/07/08/2589458.html

總結

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