Question

嗨，我是初学者，我想在点击事件上写简单，所以我在Android SDK和Eclipse中提出了这些代码：

package com.example.aplic;

import android.support.v7.app.ActionBarActivity;
import android.support.v4.app.Fragment;
import android.os.Bundle;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.TextView;

public class MainActivity extends ActionBarActivity {

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

        Button b = (Button) findViewById(R.id.button1);

        b.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View v) {
                TextView tx = (TextView) findViewById(R.id.textView1);
                tx.setText("yourtext");
            }
         });

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment())
                    .commit();
        }

    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {

        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            return rootView;
        }
    }

}

和：

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.aplic.MainActivity$PlaceholderFragment" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="@string/hello_world" />

    <Button
        android:id="@+id/button1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/textView1"
        android:layout_marginTop="110dp"
        android:layout_toRightOf="@+id/textView1" />

    <ImageView
        android:id="@+id/imageView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignLeft="@+id/button1"
        android:layout_below="@+id/button1"
        android:layout_marginTop="96dp"
        android:contentDescription="@string/abc_action_mode_done"
        android:src="@drawable/abc_ab_bottom_solid_dark_holo" />

</RelativeLayout>

问题是当我在模拟器上启动代码时它会挂起并重置，当我在真实设备中启动它时，它会关闭程序，我不知道它有什么问题，我是否使用了错误的事件？

PS：当我删除onclick事件部分时，它工作正常，但它不会对点击作出反应。

activity_main.xml：

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.deomanapp.MainActivity"
    tools:ignore="MergeRootFrame" />

Answer 1

按钮属于fragment_main.xml。

来自您的评论

名称为fragment_main.xml

它不挂。它崩溃了。您可能正在NullPointerException。

更改为

  @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
            Bundle savedInstanceState) {
       final View rootView = inflater.inflate(R.layout.fragment_main, container, false);
        Button b = (Button) rootView.findViewById(R.id.button1);

        b.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View v) {
            TextView tx = (TextView) rootview.findViewById(R.id.textView1);
            tx.setText("yourtext");
        }
     });
        return rootView;
    }

Android SDK在启动时挂起设备

1 个答案: