控件名.getBackground().setAlpha(int);   int 在0-255之间

package net.android.alpha;import android.widget.TextView;import android.os.Bundle;import android.view.ViewGroup;import android.app.Activity;import android.graphics.Color;import android.widget.LinearLayout;public class touming extends Activity { final int WRAP_CONTENT = ViewGroup.LayoutParams.WRAP_CONTENT; public void onCreate(Bundle icicle) {  super.onCreate(icicle);  LinearLayout linearLayout = new LinearLayout(this);  linearLayout.setOrientation(LinearLayout.VERTICAL);  setContentView(linearLayout);  TextView textview1 = new TextView(this);  textview1.setText("全部不透明＝255");  //textview1.setBackgroundColor(Color.argb(255, 0, 255, 0)); //背景透明度  textview1.setTextColor(Color.argb(255, 0, 255, 0));   //文字透明度  linearLayout.addView(textview1, new LinearLayout.LayoutParams(WRAP_CONTENT,    WRAP_CONTENT));  TextView textview2 = new TextView(this);  textview2.setText("部分透分155");  textview2.setBackgroundColor(Color.argb(155, 0, 255, 0));  //背景透明度  textview2.setTextColor(Color.argb(155, 0, 255, 0));  //文字透明度  linearLayout.addView(textview2, new LinearLayout.LayoutParams(WRAP_CONTENT,    WRAP_CONTENT));  TextView textview3 = new TextView(this);  textview3.setText("部分透明55");  textview3.setBackgroundColor(Color.argb(55, 0, 255, 0));  ///背景透明度  textview3.setTextColor(Color.argb(55, 0, 255, 0));  //文字透明度  linearLayout.addView(textview3, new LinearLayout.LayoutParams(WRAP_CONTENT,    WRAP_CONTENT));  TextView textview4 = new TextView(this);  textview4.setText("全部透明0");  //textview4.setBackgroundColor(Color.argb(0, 0, 255, 0)); //背景透明度  textview4.setTextColor(Color.argb(0, 0, 255, 0));  //文字透明度  linearLayout.addView(textview4, new LinearLayout.LayoutParams(WRAP_CONTENT,    WRAP_CONTENT)); }}