android app主程序启动前加载图片

android app加载启动图片需要新创建一个activity，在主activity先加载图片activity，展示过程结束后，显示主activity。具体流程如下：

一、创建图片activity的运行类

 

package com.smallart.myapplication;

import android.content.Context;
import android.content.Intent;
import android.content.res.Resources;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.Build;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.os.Handler;
import android.util.Log;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.WindowManager;
import android.widget.Toast;
import android.widget.ImageView;
import com.nostra13.universalimageloader.core.ImageLoader;
import java.lang.reflect.Method;

public class HomeActivity extends AppCompatActivity {

    private ImageView mImageView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,
                WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
        hideBottomUIMenu(this);
        setContentView(R.layout.activity_home);

    }
}

二、在AndroidManisest.xml文件中，添加activity的注册

    <application
        android:name="com.smallart.myapplication.Application"
        android:configChanges="orientation|keyboardHidden"
        android:allowBackup="true"
        android:icon="@mipmap/ic_app_icon"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_app_icon_round"
        android:largeHeap="true"
        android:supportsRtl="true"
        android:theme="@style/Theme.AppCompat.Light.NoActionBar">
        <activity android:name=".MainActivity"
            android:screenOrientation="sensorLandscape"
            android:configChanges="orientation|keyboardHidden|screenSize">
        </activity>
        <activity android:name=".HomeActivity"
            android:screenOrientation="sensorLandscape"
            android:configChanges="orientation|keyboardHidden|screenSize">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

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

三、显示图片，在HomeActivity.java中的onCreate中添加图片显示代码：

        this.mImageView = ((ImageView)findViewById(R.id.img));
        ImageLoader.getInstance().displayImage("drawable://bg_app_start.jpg", this.mImageView);

四、增加线程，5秒后切换activity，完整代码如下：

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
                WindowManager.LayoutParams.FLAG_FULLSCREEN);
        getWindow().setFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON,
                WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
        hideBottomUIMenu(this);
        setContentView(R.layout.activity_home);

        this.mImageView = ((ImageView)findViewById(R.id.img));
        ImageLoader.getInstance().displayImage("drawable://bg_app_start.jpg", this.mImageView);
        handler.sendEmptyMessageDelayed(0,5000);

    }

    private Handler handler = new Handler() {
        //Intent intent = new Intent(MainActivity.this, HomeActivity.class);
        @Override
        public void handleMessage(Message msg) {
            getHome();
            super.handleMessage(msg);
        }
    };

    public void getHome(){
        Intent intent = new Intent(HomeActivity.this, MainActivity.class);
        startActivity(intent);
        overridePendingTransition(0, 0);
        finish();
    }