ProgressDialog(三)——代码实现屏幕正中显示ProgressDialog(ProgressBar)

MainActivity如下:

package cc.testprogressdialog;

import android.os.Bundle;
import android.view.Gravity;
import android.view.View;
import android.view.ViewGroup.LayoutParams;
import android.widget.FrameLayout;
import android.widget.LinearLayout;
import android.widget.ProgressBar;
import android.app.Activity;
import android.app.ProgressDialog;
import android.content.Context;
/**
 * Demo描述:
 * 利用代码在屏幕中间位置显示ProgressDialog和ProgressBar
 * 
 * 参考资料:
 * 1 http://blog.csdn.net/lfdfhl/article/details/18913435
 * 2 http://blog.csdn.net/lfdfhl/article/details/9299075
 * 3 http://rocye.iteye.com/blog/1258936
 *   Thank you very much
 *   
 * 如果在某个线性布局中动态添加一个控件,并且想让该控件在布局中居中.
 * 也可采用createProgressBar()方法中类似的方式
 *
 */
public class MainActivity extends Activity {
	private Context mContext;
	private ProgressBar mProgressBar;
    private ProgressDialog mProgressDialog;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		//显示ProgressBar
		createProgressBar();
		//显示ProgressDialog
		//createProgressDialog();
	}
	
	private void createProgressBar(){
		mContext=this;
		//整个Activity布局的最终父布局,参见参考资料
		FrameLayout rootFrameLayout=(FrameLayout) findViewById(android.R.id.content);
		FrameLayout.LayoutParams layoutParams=
	    new FrameLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
		layoutParams.gravity=Gravity.CENTER;
		mProgressBar=new ProgressBar(mContext);
		mProgressBar.setLayoutParams(layoutParams);
		mProgressBar.setVisibility(View.VISIBLE);
		rootFrameLayout.addView(mProgressBar);
	}
	
	
	private void createProgressDialog(){
		mContext=this;
		mProgressDialog=new ProgressDialog(mContext);
		mProgressDialog.setMessage("...请您稍等...");
		mProgressDialog.show();
	}

}

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
   >

    <TextView
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="在屏幕中间位置显示ProgressDialog和ProgressBar"
        android:layout_centerHorizontal="true" />

</RelativeLayout>