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();    }}