Android学习笔记01-Activity

Android学习笔记01-Activity

1.创建Activity

import android.app.Activity;import android.os.Bundle;public class SecondActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_second);    }}

2.快捷创建监听器

    <Button         android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:onClick="click1"        />

    public void click1(View v){        //创建意图，这个是隐式意图        Intent intent = new Intent();        //设置动作        intent.setAction(Intent.ACTION_CALL);        intent.setData(Uri.parse("tel:110"));        //启动Activity        startActivity(intent);    }

3.显示启动

    //显式启动SecondActivity    public void click2(View v){        //这个是显式意图        Intent intent = new Intent();        //设置上下文和目标Activity的字节码        intent.setClass(this, SecondActivity.class);        startActivity(intent);    }

    //显式启动拨号器    public void click3(View v){        Intent intent = new Intent();        //arg0：目标Activity所在的应用的包名        //arg1：目标Activity的类名，注意要带上包名        intent.setClassName("com.android.dialer", "com.android.dialer.DialtactsActivity");        intent.setData(Uri.parse("tel:11670"));        startActivity(intent);    }

    //显示启动浏览器    public void click6(View v){        Intent intent = new Intent();        intent.setClassName("com.android.browser", "com.android.browser.BrowserActivity");        startActivity(intent);    }

4.隐式启动

    //隐式跳转至打电话Activity    public void click1(View v){        //创建意图，这个是隐式意图        Intent intent = new Intent();        //设置动作        intent.setAction(Intent.ACTION_CALL);        intent.setData(Uri.parse("tel:110"));        //启动Activity        startActivity(intent);    }

    /**     * 隐式启动拨号器     */    public void click4(View v){        Intent intent = new Intent();        intent.setAction(Intent.ACTION_DIAL);        intent.setData(Uri.parse("tel:[phone]"));        startActivity(intent);    }

        <activity android:name=".SecondActivity">            <intent-filter >                <action android:name="a.b.c"/>                <action android:name="a.b.c3"/>                <data android:scheme="heima"/>                <data android:scheme="heima3" android:mimeType="text/name"/>                <category android:name="android.intent.category.DEFAULT"/>            </intent-filter>            <intent-filter >                <action android:name="a.b.c2"/>                <data android:scheme="heima2"/>                <category android:name="android.intent.category.DEFAULT"/>            </intent-filter>        </activity>

    /**     * 隐式启动SecondActivity     */    public void click5(View v){        Intent intent = new Intent();        intent.setAction("a.b.c");        //匹配mimetype//      intent.setType("text/name");        //匹配scheme//      intent.setData(Uri.parse("heima:春眠不觉晓"));        intent.setDataAndType(Uri.parse("heima:春眠不觉晓"), "text/name");        //如果没有设置Category的匹配，那么自动匹配CATEGORY_DEFAULT//      intent.addCategory(Intent.CATEGORY_DEFAULT);        startActivity(intent);    }

5.Intent数据封装

        //跳转到SecondActivity，在second中做姻缘计算        Intent intent = new Intent(this, SecondActivity.class);        //把数据封装至intent中        //intent中可以封装数据，数据有八大基本数据类型和字符串及它们的数组，还有实现了序列化接口的对象，还有bundle对象//      intent.putExtra("maleName", maleName);//      intent.putExtra("femaleName", femaleName);        //Bundle中也可以用键值对封装数据，封装类型与intent一致        Bundle extras = new Bundle();        extras.putString("maleName", maleName);        extras.putString("femaleName", femaleName);        intent.putExtras(extras);        startActivity(intent);

            Intent intent = getIntent();//          String maleName = intent.getStringExtra("maleName");//          String femaleName = intent.getStringExtra("femaleName");            Bundle bundle = intent.getExtras();            String maleName = bundle.getString("maleName");            String femaleName = bundle.getString("femaleName");

6.简单姻缘核心代码

            String text = maleName + femaleName;            byte[] b = text.getBytes();            int total = 0;            for (byte c : b) {                total += c;            }            int yanyuan = Math.abs(total) % 101;

7.横竖屏问题

        <activity            android:screenOrientation="portrait"            android:name="com.itheima.lifecycle.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>

        //写死横屏        setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);

8.启动模式

<activity             android:launchMode="singleInstance"            android:name="com.itheima.runmode.SecondActivity"></activity>

android:launchMode="standard"android:launchMode="singleInstance"android:launchMode="singleTop"android:launchMode="singleTask"

9.隐式启动

10.隐式启动

11.隐式启动

12.隐式启动

13.隐式启动