【工具类】如何通过代码安装一个apk文件

 <?xml version="1.0" encoding="utf-8"?>
 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:orientation="vertical" >
     <TextView
         android:layout_width="fill_parent"
         android:layout_height="wrap_content"
         android:text="@string/hello" />
     <EditText
         android:id="@+id/et_path"
         android:layout_width="match_parent"
         android:layout_height="wrap_content"
         android:text="/sdcard/queryAddress.apk" />
     <Button
         android:id="@+id/button1"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:onClick="install"
         android:text="安装" />
 </LinearLayout>

 import java.io.File;
 import android.app.Activity;
 import android.content.Intent;
 import android.net.Uri;
 import android.os.Bundle;
 import android.view.View;
 import android.widget.EditText;
 public class DemoActivity extends Activity {
     private EditText et_path;
     @Override
     public void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.main);
         et_path = (EditText) this.findViewById(R.id.et_path);
     }
     public void install(View view) {
         String path = et_path.getText().toString().trim();
         Intent intent = new Intent();
         intent.setAction(Intent.ACTION_VIEW);
         // intent.setData(Uri.fromFile(new File(path)));
         // intent.setType("application/vnd.android.package-archive");
         intent.setDataAndType(Uri.fromFile(new File(path)),
                 "application/vnd.android.package-archive");
         startActivity(intent);
     }
 }