Android巧用DecorView实现对话框功能

如果还不知道DecorView，那也没有什么关系 ^_^

先来看看实现的效果

实现的大致思路

1. 首先需要明白什么是DecorView，他是android中界面的根布局。其实android的activity界面整个就是一个控件树，DecorView是根节点，DecorView的孩子节点就是一个LinearLayout，这个LinearLayout的孩子系节点就包括状态栏 + 和我们自己写的布局

2. DecorView是FramLayout的子类（可以从源码中看到）

3. 既然DecorView是根节点，而且还是FrameLayout，所以我们可以把我们自己的布局 添加到DecorView 或者 从DecorView移除，这样就模拟出了一个Dialog的效果~~ ，当然这个Dialog的样式，动画就可以自己想怎么写就怎么写了撒

4. 通过activity.getWindow().getDecorView()可以获得DecorView

[下面大量 代码 ]

第一个对话框的实现

public class TipsDialog {
 private Activity activity;
 private View rootView;
 private TextView confirmTextView;
 private TextView cancelTextView;
 private TextView contentTextView;

private boolean isShowing;

public TipsDialog(Activity activity) {
   this.activity = activity;
   isShowing = false;
   rootView = LayoutInflater.from(activity).inflate(R.layout.view_tips_dialog,null);
   confirmTextView = (TextView) rootView.findViewById(R.id.view_tips_dialog_tv_confirm);
   cancelTextView = (TextView) rootView.findViewById(R.id.view_tips_dialog_tv_cancel);
   contentTextView = (TextView) rootView.findViewById(R.id.view_tips_dialog_tv_content);

}

public void show(){
   if(activity == null){
     return;
   }
   if(isShowing){
     return;
   }
   ViewGroup decorView = (ViewGroup) activity.getWindow().getDecorView();
   FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
   params.gravity = Gravity.CENTER;
   rootView.setLayoutParams(params);
   decorView.addView(rootView);
   rootView.setOnClickListener(new View.OnClickListener() {
     @Override
     public void onClick(View v) {
       dismiss();
     }
   });

RotateAnimation rotateAnimation = new RotateAnimation(0,720f,RotateAnimation.RELATIVE_TO_SELF,0.5f,RotateAnimation.RELATIVE_TO_SELF,0.5f);
   rotateAnimation.setDuration(2000);
   contentTextView.startAnimation(rotateAnimation);

isShowing = true;
 }

public void dismiss(){
   if(!isShowing){
     return;
   }
   isShowing = false;
   if(rootView.getParent() == null){
     return;
   }
   ViewGroup parent = (ViewGroup) rootView.getParent();
   parent.removeView(rootView);

}

public int getRandomColor(){
   Random random = new Random();
   return Color.argb(random.nextInt(200),random.nextInt(240),random.nextInt(240),random.nextInt(240));
 }

public boolean isShowing() {
   return isShowing;
 }
}

其实就是show的时候将布局添加到DecorView上面去，dismiss的时候将布局从DecorView上面移除

提示的实现（没有处理完善~~ 仅仅就是说明哈DecorView）

public class TopTipDialog {
 private Activity activity;
 private View rootView;
 private boolean isShowing;
 private static final int VIEW_HEIGHT = 64;//px

public TopTipDialog(Activity activity) {
   this.activity = activity;
   rootView = LayoutInflater.from(activity).inflate(R.layout.view_top_tip_dialog,null);
 }

public void show(){

if(isShowing){
     return;
   }
   ViewGroup decorView = (ViewGroup) activity.getWindow().getDecorView();
   FrameLayout.LayoutParams params = new FrameLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, VIEW_HEIGHT);
   params.gravity = Gravity.TOP;
   params.setMargins(0,0,0,-VIEW_HEIGHT);
   rootView.setLayoutParams(params);

TranslateAnimation translateAnimation = new TranslateAnimation(0,0,-VIEW_HEIGHT,0);
   translateAnimation.setDuration(1500);
   translateAnimation.setFillAfter(true);
   decorView.addView(rootView);
   rootView.startAnimation(translateAnimation);

rootView.postDelayed(new Runnable() {
     @Override
     public void run() {
       TranslateAnimation translateAnimation1 = new TranslateAnimation(0,0,0,-VIEW_HEIGHT);
       translateAnimation1.setDuration(1500);
       translateAnimation1.setFillAfter(true);
       rootView.startAnimation(translateAnimation1);
     }
   },3000);

}
}

来源：http://www.jianshu.com/p/cbeda0a58b21#