java - 无法在第二个屏幕上制作全屏 Android 演示文稿

Question

我的问题是关于利用设备辅助屏幕的 Android 设施，即 android.app.Presentation

我正在使用这个包装器:https://github.com/commonsguy/cwac-presentation

不幸的是，我无法强制第二个屏幕布局处于全屏模式:尽管其宽度与屏幕完全匹配，但其高度始终限制在屏幕中心的条纹，大约是屏幕高度的 1/4

相应地，其所有内容都显示在这个狭窄的边界内，而屏幕的其余部分则保持黑色且无用

对于那些不了解此 API 的人，
android.app.Presentation 是一种特殊类型的 Dialog，显示在设备的辅助屏幕上，
我上面提到的包装器基于扩展了 DialogFragment 的 PresentationFragment。用户创建一个扩展 PresentationFragment 的类，并在其重写的 onCreateView() 中创建他希望在第二个屏幕上显示的布局。示例:

    public class CustomPresentationFragment extends PresentationFragment {

        public static CustomPresentationFragment newInstance(Context ctxt,
                                                             Display display) {

        CustomPresentationFragment frag=new CustomPresentationFragment();

        frag.setDisplay(ctxt, display);

        //we may prepare bundle to pass, if necessary
        //Bundle b=new Bundle();
        //b.putString("key1", value1);
        //b.putString("key2", value2);
        //frag.setArguments(b); 

        return(frag);
        }



      @Override
      public View onCreateView(LayoutInflater inflater,
                               ViewGroup container,
                               Bundle savedInstanceState) {

      View myView = new View(getContext());       

      //here we create layout that we want to be displayed on second screen, and return it

      return(myView);

      }


}

这是PresentationFragment的实现。正如我们所看到的，它包含 Presentation 变量:

package com.commonsware.cwac.preso;

import android.app.Dialog;
import android.app.DialogFragment;
import android.app.Presentation;
import android.content.Context;
import android.os.Bundle;
import android.view.Display;

public abstract class PresentationFragment extends DialogFragment
 {
   private Display display = null;
   private Presentation preso = null;

   public Dialog onCreateDialog(Bundle savedInstanceState)
   {
     if (this.preso == null) {
       return super.onCreateDialog(savedInstanceState); 

       //instead of simply returning super value, I have tried the following here,
       //with no success:
       //
       //Dialog dlg = super.onCreateDialog(savedInstanceState);
       //dlg.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
       //dlg.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
       //dlg.getWindow().setLayout(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
       //return dlg;

    }

     return this.preso;
   }

   public void setDisplay(Context ctxt, Display display) {
     if (display == null) {
       this.preso = null;
     }
     else {
       this.preso = new Presentation(ctxt, display, getTheme());

       //since Presentation is Dialog, I have tried the same here as well,
       //no success:

       //this.preso.getWindow().clearFlags(WindowManager.LayoutParams.FLAG_FORCE_NOT_FULLSCREEN);
       //this.preso.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
       //this.preso.getWindow().setLayout(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);


     }

     this.display = display;
   }

   public Display getDisplay() {
     return this.display;
   }

   protected Context getContext() {
     if (this.preso != null) {
       return this.preso.getContext();
     }

     return getActivity();
   }
}

编辑。这是我的一个PresentationFragments 中的onCreateView():

@Override
      public View onCreateView(LayoutInflater inflater,
                               ViewGroup container,
                               Bundle savedInstanceState) {

      String uri = "somefilepath";
      File imgFile = new  File(uri);
      Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());

      ImageView view = new ImageView(getContext());
      view.setImageBitmap(myBitmap);
      view.setLayoutParams(new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));

      RelativeLayout pRelative = new RelativeLayout(getContext());   
      pRelative.setLayoutParams(new RelativeLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT)); 
      pRelative.setGravity(Gravity.CENTER);

      pRelative.addView(view);

      return pRelative;       

      }

Answer 1

首先，您的 RelativeLayout 的父级可能不是另一个 RelativeLayout，因此您不应该尝试设置 RelativeLayout 的LayoutParams 是 RelativeLayout.LayoutParams 的实例。

其次，将其重写为 XML 布局并对其进行扩充。那么你的 RelativeLayout 就有更好的机会工作，因为它会在膨胀时知道它的父级。 RelativeLayout 是一个挑剔的野兽。另一种选择是从 RelativeLayout 切换到其他可以居中的东西，例如 FrameLayout。