步骤一：在项目清单跟节点加入android:installLocation="internalOnly",指定你的app安装到内存中。
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
package="com.xxxxxx.xxx"
android:installLocation="internalOnly">
步骤二：在第一个要启动的activity的filter中加入<intent-filter>，让app成为主程序。
<activity
android:name=".ui.SplashAty"
android:theme="@style/AppSplash">
<intent-filter>
<action android:name="android.intent.action.MAIN" />

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

！！！！！！！！！完工！！！！！！！！！！！

Android默认桌面设置终级大招

最近研究桌面程序开发，遇到一个难题，就是按Home键没法选择自己的桌面作为默认桌面，经过一番辛苦的查找组合，终于从各个旮旯挖出代码，然后组合修改，调试，终于修成正果。各位看官，直接看代码：

import android.app.Activity;
import android.app.WallpaperManager;
import android.content.BroadcastReceiver;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.graphics.Color;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.provider.Contacts;
import android.provider.Settings;
import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.support.v7.widget.GridLayout;
import android.text.SpannableString;
import android.text.Spanned;
import android.text.style.RelativeSizeSpan;
import android.text.style.SuperscriptSpan;
import android.util.DisplayMetrics;
import android.util.Log;
import android.util.TypedValue;
import android.view.KeyEvent;
import android.view.View;
import android.view.WindowManager;
import android.widget.DigitalClock;
import android.widget.ImageView;
import android.widget.LinearLayout;
import android.widget.TextView;

import com.disney.sclocker.R;
import com.disney.sclocker.alarm.ClockAlarmActivity;
import com.disney.sclocker.locker.ScreenLockService;
import com.disney.sclocker.util.Utils;
import com.disney.sclocker.widget.DisneyAnalogClockV1;
import com.disney.sclocker.widget.GuideViewPager;

import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;

public class DesktopActivity extends Activity {

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    


    setContentView(R.layout.activity_desktop);
    
    //HOME键侦测
    IntentFilter homeFilter = new IntentFilter(Intent.ACTION_CLOSE_SYSTEM_DIALOGS);
    registerReceiver(homeReceiver, homeFilter);
    Log.d("123", "android.os.Build.MANUFACTURER=" + android.os.Build.MANUFACTURER);
}




@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
    switch (keyCode) {
        case KeyEvent.KEYCODE_BACK:
            return true;
        case KeyEvent.KEYCODE_HOME:
            return true;
    }
    return super.onKeyDown(keyCode, event);
}




//Home键侦测---[----
private final BroadcastReceiver homeReceiver = new BroadcastReceiver() {
    final String SYS_KEY = "reason"; // 标注下这里必须是这么一个字符串值


    final String SYS_HOME_KEY = "homekey";// 标注下这里必须是这么一个字符串值


    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (action.equals(Intent.ACTION_CLOSE_SYSTEM_DIALOGS)) {
            String reason = intent.getStringExtra(SYS_KEY);
            if (reason != null && reason.equals(SYS_HOME_KEY)) {
                Log.i("TT", "home键监听");
                String currentHome = getHomeLauncher();
                Log.i("TT", "currentHome="+currentHome);
                if (isDefaultHome()) {
                    return;
                }
                setDefaultL();




            }
        }
    }
};


private void setDefaultL(){


    Intent intent = new Intent(Intent.ACTION_MAIN);
    intent.addCategory("android.intent.category.HOME");
    try {
        intent.setComponent(new ComponentName("android","com.android.internal.app.ResolverActivity"));
        startActivity(intent);
    }catch (Exception e){//这里就是为了处置华为手机的
        try {

intent.setComponent(new ComponentName("com.huawei.android.internal.app", "com.huawei.android.internal.app.HwResolverActivity"));//这个类有些华为手机找不到
startActivity(intent);
} catch (Exception e1){
e1.printStackTrace();
try {
startHuaweiSettingActOfDefLauncher();//开启桌面设置
}catch(Exception e2){
e2.printStackTrace();
intent = new Intent(Settings.ACTION_APPLICATION_SETTINGS);//还不行，就只能应用程序设置了
startActivity(intent);
}

        }
    }
}


/**
 * 判断自己是否为默认桌面
 */
public final boolean isDefaultHome() {
    Intent intent = new Intent(Intent.ACTION_MAIN);//Intent.ACTION_VIEW
    intent.addCategory("android.intent.category.HOME");
    intent.addCategory("android.intent.category.DEFAULT");
    PackageManager pm = getPackageManager();
    ResolveInfo info = pm.resolveActivity(intent, PackageManager.MATCH_DEFAULT_ONLY);
    boolean isDefault = getPackageName().equals(info.activityInfo.packageName);
    return isDefault;
}


public void startHuaweiSettingActOfDefLauncher() {
    IntentFilter localIntentFilter = new IntentFilter();
    localIntentFilter.addAction(Intent.ACTION_MAIN);//"android.intent.action.MAIN"
    localIntentFilter.addCategory(Intent.CATEGORY_HOME);//"android.intent.category.HOME"
    Intent localIntent3 = new Intent(localIntentFilter.getAction(0));
    localIntent3.addCategory(localIntentFilter.getCategory(0));
    Intent localIntent4 = new Intent();
    localIntent4.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
    localIntent4.setClassName("com.android.settings", "com.android.settings.Settings$PreferredSettingsActivity");
    localIntent4.putExtra("preferred_app_package_name", getPackageName());
    localIntent4.putExtra("preferred_app_class_name", DesktopActivity.class.getName());
    localIntent4.putExtra("is_user_confirmed", true);
    localIntent4.putExtra("preferred_app_intent", localIntent3);
    localIntent4.putExtra("preferred_app_intent_filter", localIntentFilter);
    localIntent4.putExtra("preferred_app_label", "默认桌面设置");
    startActivity(localIntent4);
}





private String getHomeLauncher() {
    Intent intent = new Intent(Intent.ACTION_MAIN);
    intent.addCategory(Intent.CATEGORY_HOME);
    ResolveInfo resolveInfo = getPackageManager().resolveActivity(intent, 0);
    String currentHomePackage = resolveInfo.activityInfo.packageName;
    return currentHomePackage;
}


@Override
protected void onDestroy() {
    unregisterReceiver(homeReceiver);
    super.onDestroy();
}

}