Android如何在App中启动系统闹钟

package com.demo.cxc.systemclocksample; 
 
import android.content.Intent; 
import android.content.pm.ApplicationInfo; 
import android.content.pm.PackageInfo; 
import android.os.Bundle; 
import android.os.Handler; 
import android.os.Message; 
import android.support.v7.app.AppCompatActivity; 
import android.util.Log; 
import android.view.View; 
import android.widget.Button; 
import android.widget.Toast; 
 
import java.util.ArrayList; 
import java.util.List; 
 
public class MainActivity extends AppCompatActivity { 
  private Button startSystemClockButton = null; 
 
 
  private List allPackageInfos;//系统安装所有软件 
  private List clockPackageInfos;//系统时钟软件 
 
  private static final int HANDLE_MESSAGE_KEY = 1001; 
  private Handler myHandler = new Handler() { 
    @Override 
    public void handleMessage(Message msg) { 
      super.handleMessage(msg); 
      if (msg != null) { 
        switch (msg.what) { 
          case HANDLE_MESSAGE_KEY: 
            Toast.makeText(getApplicationContext(), "--app scan over--", Toast.LENGTH_SHORT).show(); 
            Log.d("CXC", "--app scan over--"); 
            break; 
 
          default: 
            break; 
 
        } 
 
      } 
 
    } 
  }; 
 
  @Override 
  protected void onCreate(Bundle savedInstanceState) { 
    super.onCreate(savedInstanceState); 
    setContentView(R.layout.activity_main); 
    initViews(); 
    initData(); 
 
    //begin scan installed applications; 
    //// TODO: 16/1/15 
    new Thread(new ScanInstalledAppsRunnable()).start(); 
  } 
 
  private void initViews() { 
    startSystemClockButton = (Button) findViewById(R.id.start_system_clock_bt); 
    startSystemClockButton.setOnClickListener(new View.OnClickListener() { 
      @Override 
      public void onClick(View v) { 
        //// TODO: 16/1/15 
        startSystemClock(); 
      } 
    }); 
  } 
 
  private void initData() { 
    clockPackageInfos = new ArrayList(); 
  } 
 
 
  class ScanInstalledAppsRunnable implements Runnable { 
    @Override 
    public void run() { 
      allPackageInfos = getPackageManager() 
          .getInstalledPackages(0); 
 
      if (allPackageInfos == null || allPackageInfos.size() == 0) { 
        //// TODO: 16/1/15 todo nothing 
        return; 
      } 
 
      if (clockPackageInfos == null) { 
        clockPackageInfos = new ArrayList(); 
      } 
 
      PackageInfo tempPackageInfo = null; 
      for (int i = 0; i