Android——Activity跳转

Activity_main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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: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="com.hanqi.text3.MainActivity">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Hello World!"
        android:id="@+id/textView" />

    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="跳转页面"
        android:id="@+id/mybutton"
        android:layout_below="@+id/textView"
        android:layout_toRightOf="@+id/textView"
        android:layout_toEndOf="@+id/textView"
        android:layout_marginTop="78dp"
        android:onClick="onMyButtonClick"
        />
</RelativeLayout>

MainActivity.java

package com.hanqi.text3;

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

//继承了Activity
public class MainActivity extends Activity {

    @Override //覆盖  重写了父类的onCreate()
    protected void onCreate(Bundle savedInstanceState) {
        //super  父类
        //调用了父类的方法
        super.onCreate(savedInstanceState);
        //设置Java代码和layout文件的关联
        //通过R文件的id值
        setContentView(R.layout.activity_main);
    }
    //按钮点击事件的回调函数
    public void onMyButtonClick(View v)
    {
        Log.e("ATG","按钮点击事件触发");
       // Activity2 a2= new Activity2();
        //先创建意图 Intent
        //第一个参数 来源实例， 就是当前Activity实例
        //第二个参数 目标类， 目标Activity的class
        Intent in = new Intent(this,Activity2.class);

        //发动意图
        startActivity(in);

    }
}

需要注意的是这个方法必须符合三个条件：1.public　　2.返回void　　3.只有一个参数View，这个View就是被点击的这个控件。

activity2.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"

        android:text="大家好"

        />
    <EditText
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:id="@+id/et"
        />
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="跳转下一个"
        android:onClick="onbuttonclick"
        />

</LinearLayout>

Activity2.java

package com.hanqi.text3;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.util.Log;
import android.view.View;
import android.widget.EditText;

/**
 * Created by Administrator on 2016/3/16.
 */
//回调方法
public class Activity2 extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);

        //
        setContentView(R.layout.activity2);

        System.out.println("这是我运行的第一个Activity");

    //    Log.d("text", "log输出的信息");
  //      Log.w("text", "log输出的信息");
  //      Log.e("text", "log输出的信息");
 //       Log.i("text","log输出的信息");
 //       Log.v("text","log输出的信息");

        Log.e("TAG","######创建");


    }
    @Override
   protected void onStart(){
       super.onStart();

       Log.e("ATG","######启动");

    }
    @Override
    protected void onResume(){
        super.onResume();
        Log.e("ATG", "######显示");
    }

    @Override
    protected void onPause(){
        super.onPause();
        Log.e("ATG", "######暂停");
    }
    @Override
    protected void onStop(){
        super.onStop();
        Log.e("ATG", "######停止");
    }
    @Override
    protected void onRestart(){
        super.onRestart();
        Log.e("ATG", "######重新启动");
    }
    //回调方法
    //1.在暂停之后和停止之前保存
    int i=0;
    String etkey ="edittext";//成员变量
    EditText et;
    @Override
    protected void onSaveInstanceState(Bundle outState) {
        //Bundle实际是一个Map，可以存储键值对key/value
        i++;
        Log.e("ATG","保存="+i);

        outState.putInt("myKey",i);

        super.onSaveInstanceState(outState);

        //保存用户的输入信息
        //EditText
        //使用id查找并获取View的实例
         et= (EditText)findViewById(R.id.et);

        String str=et.getText().toString();//局部变量

        Log.e("TAG","获取用户输入="+str);
        outState.getString("edittext",str);

    }


    //2.恢复销毁前的保持状态
    @Override
    protected void onRestoreInstanceState(Bundle savedInstanceState) {
        super.onRestoreInstanceState(savedInstanceState);

       i = savedInstanceState.getInt("myKey");
        Log.e("ATG", "获取="+i);

        //恢复用户数据
        String str = savedInstanceState.getString(etkey);
        Log.e("ATG", "获取str="+str);
        //设置输入框里面的内容
        //操作View的实例
        et = (EditText)findViewById(R.id.et);
        et.setText(str);
    }

    @Override
    protected void onDestroy(){
        super.onDestroy();
        Log.e("ATG", "######销毁");
    }


    public void onbuttonclick(View v)
    {
        Intent in = new Intent(this,Activity3.class);

        startActivity(in);
    }

}

activity3.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent">


    <Button
        android:layout_width="100dp"
        android:layout_height="wrap_content"
        android:text="关闭"
        android:onClick="onClick"
        />
</LinearLayout>

Activity3.java

package com.hanqi.text3;

import android.app.Activity;
import android.os.Bundle;
import android.os.PersistableBundle;
import android.view.View;

/**
 * Created by Administrator on 2016/3/19.
 */
public class Activity3 extends Activity {

    @Override
    public void onCreate(Bundle savedInstanceState, PersistableBundle persistentState) {
        super.onCreate(savedInstanceState, persistentState);

        setContentView(R.layout.activity3);
    }
    public void onClick(View v)
    {
        //关闭
        finish();
    }
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.hanqi.text3">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">

        <activity android:name=".Activity2"

            >
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>

        </activity>
        <activity android:name=".Activity3"

            >
            <intent-filter>
                <action android:name="android.intent.action.VIEW" />

                <category android:name="android.intent.category.DEFAULT" />
            </intent-filter>

        </activity>

        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>