Android学习4:Android的Activity小记

最新推荐文章于 2025-12-28 15:22:55 发布

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#Activity

本文详细介绍了 Android 开发中 Activity 的基本使用方法，包括如何在 AndroidManifest.xml 中注册 Activity，通过 Intent 实现 Activity 之间的跳转及数据传递。

上周五又照虎画猫的学习了一下 , Android的 Activity 事件..

代码还是自已写出来的, 记忆比较深刻.. 作为一个小的积累, 记录一下.

Android 的 Activity 需要在 AndroidMainfest.xml 中注册, 注册方法也很简单:

如下.

在xml中添加<activity> 来声明.

<activity
    android:name=".Activity2"
    android:label="Activity2">
</activity>

Activity01: Activity02:

代码如下:

src/main/AndroidManifest.xml

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

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme">
        <activity
            android:name=".MainActivity"
            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=".Activity2"
            android:label="Activity2">
        </activity>
    </application>

</manifest>

layout/activity_main.xml

<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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">

    <TextView android:text="@string/hello_world" android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/textView"
        android:layout_centerVertical="true"
        android:layout_centerHorizontal="true" />

    <LinearLayout
        android:orientation="horizontal"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:layout_alignParentTop="true"
        android:layout_alignParentLeft="true"
        android:layout_alignParentStart="true">

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="调用Activity02"
            android:id="@+id/button1" />

        <Button
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="调用外部Activity"
            android:id="@+id/button2" />
    </LinearLayout>

</RelativeLayout>

layout/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">

    <LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">

        <Button
            android:layout_width="115dp"
            android:layout_height="wrap_content"
            android:text="后退"
            android:id="@+id/btnBack" />

        <ImageView
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:id="@+id/imageView"
            android:src="#ff5d7d59" />
    </LinearLayout>

</LinearLayout>

com/example/youtwo/testactivity/MainActivity.java

package com.example.youtwo.testactivity;

import android.content.Context;
import android.content.Intent;
import android.net.Uri;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;


public class MainActivity extends ActionBarActivity {

    Button btnActivity_1;
    Button btnOutside;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Log.e("Activity1", "onCreate()");

        //  初始化按钮
        btnActivity_1 = (Button) this.findViewById(R.id.button1);
        btnActivity_1.setOnClickListener(new ClickEvent());

        btnOutside = (Button) this.findViewById(R.id.button2);
        btnOutside.setOnClickListener(new ClickEvent());
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    @Override
    public void onDestroy() {
        super.onDestroy();
        Log.e("Activity1", "onDestroy()");
    }

    @Override
    public void onStart() {
        super.onStart();
        Log.e("Activity1", "onStart()");
    }

    @Override
    public void onResume() {
        super.onResume();
        Log.e("Activity1", "onResume()");
    }

    class ClickEvent implements View.OnClickListener {

        @Override
        public void onClick(View v) {
            if (v == btnActivity_1) {
                Intent intent = new Intent();
                intent.setClass(MainActivity.this, Activity2.class);

//                // new一个Bundle对象，并将要传递的数据传入
//                Bundle bundle = new Bundle();
//                // bundle.putString("Text",tbBundle.getText().toString());
//
//                // 将Bundle对象assign给Intent
//                intent.putExtras(bundle);

                // 调用Activity2
                startActivity(intent);

//                //会触发onDestroy();
//                MainActivity.this.finish();
            } else if (v == btnOutside) {
                Uri uri = Uri.parse("http://www.baidu.com");
                Intent it = new Intent(Intent.ACTION_VIEW, uri);
                startActivity(it);
            }
        }
    }


}

com/example/youtwo/testactivity/Activity2.java

package com.example.youtwo.testactivity;

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

/**
 * Created by YouTwo on 2015/1/16.
 */
public class Activity2 extends Activity {

    Button btnBack;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity2);
        Log.e("Activity2", "onCreate()");

        btnBack = (Button)this.findViewById(R.id.btnBack);
        btnBack.setOnClickListener(new ClickEvent());
    }

    class ClickEvent implements View.OnClickListener {

        @Override
        public void onClick(View v) {
            if(v == btnBack) {
                //Intent intent = new Intent();
                //intent.setClass(Activity2.this, Activity.class);
                //startActivity(intent);

                finish();
            }
        }
    }
}

本文只测试了简单的 Activity 调用方法.

Acivity 的传值, 使用Bundle,

// new一个Bundle对象，并将要传递的数据传入
Bundle bundle = new Bundle();
bundle.putString("Text",tbBundle.getText().toString());

// 将Bundle对象assign给Intent
intent.putExtras(bundle);

接收数据使用 getIntent().getExtras();.方法:

//得Intent中的Bundle对象
Bundle bunde = this.getIntent().getExtras();

//取得Bundle对象中的数据
bunde.getString("Text")

黑色星期一.. 开森, 麻麻的..