android studio实现两个应用程序之间的跳转问题
jam96 2016-09-06 11:22:56 第一个程序:通过点击按钮来跳转
跳转代码:
public class MainActivity extends AppCompatActivity {
private Button bt;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
bt=(Button)findViewById(R.id.bt1);
bt.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//第一个参数是另一个程序的包名
//第二个参数是要启动的activity
ComponentName componentName =new ComponentName("com.example.app_tiaozhuan2","com.example.app_tiaozhuan2.MainActivity");
try{
Intent intent=new Intent();
intent.setComponent(componentName);
startActivity(intent);
}catch (Exception e){
Toast.makeText(getApplicationContext(),"没有找到应用程序",Toast.LENGTH_SHORT).show();
}
}
});
}
}
但程序崩了,根本运行不起来,错误提示是:
Process: com.example.administrator.app_tiaozhuan, PID: 17879
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.example.administrator.app_tiaozhuan/com.example.administrator.app_tiaozhuan.MainActivity}: java.lang.NullPointerException: Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference
求大神指教啊!