在呼叫其他activity類中的方法是，出現錯誤；

錯誤方法：MainActivity activity=new MainActivity();

錯誤原因：activity是不能用new來例項化的。

解決辦法：在activity類的onCreate()中 呼叫該類的構造方法,把context和avtivity物件傳過來。話不多說，程式碼更直觀！

1.ClipBoardService.java

public class ClipBoardService {
	
	private Context contxt;
	private MainActivity activity;

	public Context getContxt() {
		return contxt;
	}

	public void setContxt(Context contxt) {
		this.contxt = (MainActivity) contxt;
	}

	public Activity getActivity() {
		return (MainActivity) activity;
	}

	public void setActivity(Activity activity) {
		this.activity = (MainActivity) activity;
	}

	public ClipBoardService(Context context, MainActivity activity) {
		this.setContxt(context);
		this.setActivity(activity);
	}
private void getMethod(){
		activity.method();
	}
}
 

public class MainActivity extends Activity{
      private ClipBoardService clipBoard;
    
      @Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		clipBoard = new ClipBoardService(this,MainActivity.this);
   }public void method(){}
}