先给大家展示下效果图，大家觉效果满意，请参考实现代码。

直接上代码：

private void setDialog(){
View view = getLayoutInflater().inflate(R.layout.dialog_country, null);
mDialog = new Dialog(this);
mDialog.setContentView(view, new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.WRAP_CONTENT));
Window window = mDialog.getWindow();
WindowManager.LayoutParams wl = window.getAttributes();
wl.x = 0;
wl.y = getWindowManager().getDefaultDisplay().getHeight();
wl.width = ViewGroup.LayoutParams.MATCH_PARENT;
wl.height = ViewGroup.LayoutParams.WRAP_CONTENT;
mDialog.onWindowAttributesChanged(wl);
mDialog.setCanceledOnTouchOutside(true);
mDialog.show();
Button btnChina = (Button) view.findViewById(R.id.btnChina);
Button btnUSA = (Button) view.findViewById(R.id.btnUSA);
Button btnUK = (Button) view.findViewById(R.id.btnUK);
Button btnCancel = (Button) view.findViewById(R.id.btnCancel);
btnChina.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
mQuery.id(R.id.btnCountry).getTextView().setText("China");
mDialog.dismiss();
} 
});
btnUSA.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
mQuery.id(R.id.btnCountry).getTextView().setText("USA");
mDialog.dismiss();
} 
});
btnUK.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
mQuery.id(R.id.btnCountry).getTextView().setText("UK");
mDialog.dismiss();
} 
});
btnCancel.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
mDialog.dismiss();
} 
});
}

首先inflate一个xml文件，产生一个view；再创建一个Dialog，设置Dialog的View为inflate的view；然后通过WindowManager.LayoutParams设置Dialog的长度、宽度、显示的位置等等，最后setCanceledOnTouchOutside(true)，点击其他地方可以退出Dialog。