Android Intent实现页面之间跳转

什么是Intent
Intent可以理解为信使（意图）
由Intent来协助完成Android各个组件之间的通讯
Intent实现页面逐渐的跳转
1.startActivity(inetnt)
2.startActivityForResult(intent, requestCode);
 onAcitivtyResult(int requestCode, int resultCode, Intent data)
 setResult(resultCode, data);
 
先创建两个xml文件firstactivity.xml和secondactivity.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"
    android:orientation="vertical" >

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="通过Intent实现页面之间的跳转\n通过按钮1实现无返回结果的页面跳转\n通过按钮2实现有返回结果的页面跳转" />

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="按钮1" />

    <Button
        android:id="@+id/button2"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="按钮2" />

    <TextView
        android:id="@+id/textView1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="页面跳转后的结果将会显示在这里" />

</LinearLayout>

firstactivity.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"
    android:orientation="vertical" >

    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="点击返回第一个Activity" />

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Button" />

</LinearLayout>

secondactivity.xml

在AndroidManifest.xml中注册这两个xml，并设置firstactivity.xml是启动的时候加载的xml。

        <activity
            android:name="com.example.intentdemo.FirstActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
        <activity
            android:name="com.example.intentdemo.SecondActivity"
            android:label="@string/app_name" >
        </activity>

FirstActivity.java的buttton1用于通过startActivity()方法实现跳转。

        button1.setOnClickListener(new OnClickListener() {

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

FirstActivity.java的buttton2用于通过startActivityWithResult()方法实现跳转。

        button2.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                Intent intent = new Intent(FirstActivity.this, SecondActivity.class);
                int requestCode = 1;    // 自己取的
                startActivityForResult(intent, requestCode);
            }

        });

第二个Activity返回结果并通过finish()销毁自己。

        button.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View view) {
                int resultCode = 2;
                Intent data = new Intent();
                data.putExtra("data", "这是第二个Activity返回的结果");
                setResult(resultCode, data);
                finish();
            }
        });
    }

第一个Activity通过onActivityResult()方法得到返回的结果并显示在TextView中。

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 1 && resultCode == 2) {
            textView.setText(data.getStringExtra("data"));
        }
    }

package com.example.intentdemo;

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

public class FirstActivity extends Activity {

    private Button button1;
    private Button button2;
    private TextView textView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.firstactivity);

        textView = (TextView) findViewById(R.id.textView1);

        button1 = (Button) findViewById(R.id.button1);
        button1.setOnClickListener(new OnClickListener() {

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

        button2 = (Button) findViewById(R.id.button2);
        button2.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View arg0) {
                Intent intent = new Intent(FirstActivity.this, SecondActivity.class);
                int requestCode = 1;    // 自己取的
                startActivityForResult(intent, requestCode);
            }

        });
    }

    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (requestCode == 1 && resultCode == 2) {
            textView.setText(data.getStringExtra("data"));
        }
    }
}

FirstActivity.java

package com.example.intentdemo;

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

public class SecondActivity extends Activity {

    private Button button;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.secondactivity);

        button = (Button) findViewById(R.id.button1);
        button.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View view) {
                int resultCode = 2;
                Intent data = new Intent();
                data.putExtra("data", "这是第二个Activity返回的结果");
                setResult(resultCode, data);
                finish();
            }
        });
    }

}

SecondActivity.java

效果：