Android代码优化----Application节点的模板写法及UI工具类

一、 MyApplication类的编写：

新建一个类MyApplication，继承自Application。代码如下：

MyApplication.java:

package com.smyhvae.homepicdemo;

import android.app.Application;
import android.os.Handler;
import android.os.Looper;

/**
 * Created by smyhvae on 2015/5/13.
 */
public class MyApplication extends Application {
    //获取到主线程的上下文
    private static MyApplication mContext = null;
    //获取到主线程的handler
    private static Handler mMainThreadHandler = null;
    //获取到主线程的looper
    private static Looper mMainThreadLooper = null;
    //获取到主线程
    private static Thread mMainThead = null;
    //获取到主线程的id
    private static int mMainTheadId;

    @Override
    public void onCreate() {
        // TODO Auto-generated method stub
        super.onCreate();
        this.mContext = this;
        this.mMainThreadHandler = new Handler();
        this.mMainThreadLooper = getMainLooper();
        this.mMainThead = Thread.currentThread();
        //android.os.Process.myUid()   获取到用户id
        //android.os.Process.myPid()获取到进程id
        //android.os.Process.myTid()获取到调用线程的id
        this.mMainTheadId = android.os.Process.myTid();
    }

    public static MyApplication getApplication() {
        return mContext;
    }

    public static Handler getMainThreadHandler() {
        return mMainThreadHandler;
    }

    public static Looper getMainThreadLooper() {
        return mMainThreadLooper;
    }

    public static Thread getMainThread() {
        return mMainThead;
    }

    public static int getMainThreadId() {
        return mMainTheadId;
    }

}

上面的所有代码每次在开发一个新的app时都需要用到的，然后具体到不同的项目，再继续添加不同的东西。

然后记得在清单文件中进行声明：

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" 
        android:name=".MyApplication">

需要声明的是上方代码的第6行android:name的属性。

二、UI工具类的编写：

这个工具类也是在app开发中经常用到的。可以直接copy。代码如下：

UIUtils.java:

package com.smyhvae.homepicdemo.utils;

import android.content.Context;
import android.content.Intent;
import android.content.res.ColorStateList;
import android.content.res.Resources;
import android.graphics.drawable.Drawable;
import android.os.Handler;
import android.view.LayoutInflater;
import android.view.View;

import com.smyhvae.homepicdemo.MyApplication;

/**
 * Created by smyhvae on 2015/5/13.
 */

public class UIUtils {

    
    public static Context getContext() {
        return MyApplication.getApplication();
    }

    public static Thread getMainThread() {
        return MyApplication.getMainThread();
    }

    public static long getMainThreadId() {
        return MyApplication.getMainThreadId();
    }

    /** dip转换px */
    public static int dip2px(int dip) {
        final float scale = getContext().getResources().getDisplayMetrics().density;
        return (int) (dip * scale + 0.5f);
    }

    /** pxz转换dip */
    public static int px2dip(int px) {
        final float scale = getContext().getResources().getDisplayMetrics().density;
        return (int) (px / scale + 0.5f);
    }

    /** 获取主线程的handler */
    public static Handler getHandler() {
        return MyApplication.getMainThreadHandler();
    }

    /** 延时在主线程执行runnable */
    public static boolean postDelayed(Runnable runnable, long delayMillis) {
        return getHandler().postDelayed(runnable, delayMillis);
    }

    /** 在主线程执行runnable */
    public static boolean post(Runnable runnable) {
        return getHandler().post(runnable);
    }

    /** 从主线程looper里面移除runnable */
    public static void removeCallbacks(Runnable runnable) {
        getHandler().removeCallbacks(runnable);
    }

    public static View inflate(int resId){
        return LayoutInflater.from(getContext()).inflate(resId,null);
    }

    /** 获取资源 */
    public static Resources getResources() {
        
        return getContext().getResources();
    }

    /** 获取文字 */
    public static String getString(int resId) {
        return getResources().getString(resId);
    }

    /** 获取文字数组 */
    public static String[] getStringArray(int resId) {
        return getResources().getStringArray(resId);
    }

    /** 获取dimen */
    public static int getDimens(int resId) {
        return getResources().getDimensionPixelSize(resId);
    }

    /** 获取drawable */
    public static Drawable getDrawable(int resId) {
        return getResources().getDrawable(resId);
    }

    /** 获取颜色 */
    public static int getColor(int resId) {
        return getResources().getColor(resId);
    }

    /** 获取颜色选择器 */
    public static ColorStateList getColorStateList(int resId) {
        return getResources().getColorStateList(resId);
    }
    //判断当前的线程是不是在主线程 
    public static boolean isRunInMainThread() {
        return android.os.Process.myTid() == getMainThreadId();
    }
    
    public static void runInMainThread(Runnable runnable) {
        if (isRunInMainThread()) {
            runnable.run();
        } else {
            post(runnable);
        }
    }

    public static void startActivity(Intent intent){
//        BaseActivity activity = BaseActivity.getForegroundActivity();
//        if(activity != null){
//            activity.startActivity(intent);
//        }else{
//            intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
//            getContext().startActivity(intent);
//        }
    }

    /** 对toast的简易封装。线程安全，可以在非UI线程调用。 */
    public static void showToastSafe(final int resId) {
        showToastSafe(getString(resId));
    }

    /** 对toast的简易封装。线程安全，可以在非UI线程调用。 */
    public static void showToastSafe(final String str) {
        if (isRunInMainThread()) {
            showToast(str);
        } else {
            post(new Runnable() {
                @Override
                public void run() {
                    showToast(str);
                }
            });
        }
    }

    private static void showToast(String str) {
//        BaseActivity frontActivity = BaseActivity.getForegroundActivity();
//        if (frontActivity != null) {
//            Toast.makeText(frontActivity, str, Toast.LENGTH_LONG).show();
//        }
    }
}