Question

当我点击第一个片段的按钮时，我试图将textview中的值增加1秒。没有IDE（eclipse）检测到错误。当我运行应用程序并单击按钮时，会出现一个对话框，说[不幸的是，苹果（我的应用程序名称）已经停止]。我google并发现我们应该使用界面进行交流。但我想知道我在哪里犯了错误。我正在应用的概念错误。请帮助我...

MainActivity.Java

package com.iphone.apple;

import android.os.Bundle;
import android.support.v4.app.FragmentActivity;

public class MainActivity extends FragmentActivity {

MyFragment_2 ob;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    ob = new MyFragment_2();

}

public void run(int count) {
    ob.rockon(count);
  }

}

FirstFragment

package com.iphone.apple;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;

public class MyFragment extends Fragment implements OnClickListener {
int counter = 0;
Button mButton;
MainActivity ob;

@Override
public View onCreateView(LayoutInflater inflater,
        @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    return inflater.inflate(R.layout.myfragment, container, false);
}

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);
    mButton = (Button) getView().findViewById(R.id.button1);
    mButton.setOnClickListener(this);
    ob = new MainActivity();
}

@Override
public void onClick(View arg0) {
    // TODO Auto-generated method stub
    counter++;
    ob.run(counter);
}

}

SecondFragment

package com.iphone.apple;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

public class MyFragment_2 extends Fragment {
  TextView ob = null;

@Override
public View onCreateView(LayoutInflater inflater,
        @Nullable ViewGroup container, @Nullable Bundle savedInstanceState)             {
    // TODO Auto-generated method stub
    return inflater.inflate(R.layout.fragment_2, container, false);
}

@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
    // TODO Auto-generated method stub
    super.onActivityCreated(savedInstanceState);
    ob = (TextView) getView().findViewById(R.id.textview);
}

public void rockon(int count) {
    ob.setText("count:"+count);
     }
  }

Answer 1

    ob = new MainActivity();

您必须永远不要自己实例化活动。这是Android框架的责任。

无法理解片段之间的通信？

1 个答案: