如何在Android Studio中的Contextmenu中创建编辑按钮

Question

在开始时说出来 - 我不是一个优秀的程序员。

我试图用删除和编辑功能创建一个上下文菜单，但我有点编辑功能有问题。一旦用户按下上下文菜单中的编辑按钮，他就应该能够更改长按按钮的名称以打开上下文菜单。

@Override
public boolean onContextItemSelected(MenuItem item){


    switch(item.getItemId()){
        case R.id.Bearbeiten:
        EditText editText = (EditText) findViewById(R.id.editText);
            buttonActOne.setText(editText.getText());
            return true;

当然，一旦用户按下编辑按钮，程序就会一直崩溃，并且我有点想法我是怎么做到的。

我真的希望有人能给我一个很好的答案。

编辑：

好的，首先要感谢答案。我发布了我的完整MainActivity.java

package com.example.michl.myapplication5;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.ContextMenu;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;


public class MainActivity extends Activity  {


private TextView textViewIntro;


public Button buttonActOne;
public Button buttonActTwo;
public Button buttonActThree;
public Button buttonActFour;
public Button buttonActFive;
public Button buttonActSix;
public Button buttonActSeven;
public Button buttonActEight;
public Button buttonActNine;





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



    textViewIntro = (TextView) findViewById(R.id.textViewIntro);


    Button ButtonActOne = (Button) findViewById(R.id.buttonActOne);
    ButtonActOne.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, Seite_zwei.class));   
            Button ButtonActOne = (Button)findViewById(R.id.buttonActOne);
            registerForContextMenu(ButtonActOne);


        }
    });



    Button ButtonActTwo = (Button) findViewById(R.id.buttonActTwo);

    ButtonActTwo.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, Seite_drei.class));

            Button ButtonActTwo = (Button)findViewById(R.id.buttonActTwo);
            registerForContextMenu(ButtonActTwo);
        }
    });

    Button ButtonActThree = (Button) findViewById(R.id.buttonActThree);

    ButtonActThree.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, Seite_vier.class));

            Button ButtonActThree = (Button)findViewById(R.id.buttonActThree);
            registerForContextMenu(ButtonActThree);
        }
    });
    Button ButtonActFour = (Button) findViewById(R.id.buttonActFour);

    ButtonActFour.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, Seite_fuenf.class));

            Button ButtonActFour = (Button)findViewById(R.id.buttonActFour);
            registerForContextMenu(ButtonActFour);
        }
    });
    Button ButtonActFive = (Button) findViewById(R.id.buttonActFive);

    ButtonActFive.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, Seite_sechs.class));

            Button ButtonActFive = (Button)findViewById(R.id.buttonActFive);
            registerForContextMenu(ButtonActFive);
        }
    });
    Button ButtonActSix = (Button) findViewById(R.id.buttonActSix);

    ButtonActSix.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, Seite_sieben.class));

            Button ButtonActSix = (Button)findViewById(R.id.buttonActSix);
            registerForContextMenu(ButtonActSix);
        }
    });
    Button ButtonActSeven = (Button) findViewById(R.id.buttonActSeven);

    ButtonActSeven.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, Seite_acht.class));

            Button ButtonActSeven = (Button)findViewById(R.id.buttonActSeven);
            registerForContextMenu(ButtonActSeven);
        }
    });
    Button ButtonActEight = (Button) findViewById(R.id.buttonActEight);

    ButtonActEight.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            startActivity(new Intent(MainActivity.this, Seite_neun.class));

            Button ButtonActEight = (Button)findViewById(R.id.buttonActEight);
            registerForContextMenu(ButtonActEight);
        }
    });



}


@Override
public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
    super.onCreateContextMenu(menu, v, menuInfo);

    getMenuInflater().inflate(R.menu.menu_main, menu);
}

@Override
public boolean onContextItemSelected(MenuItem item){


    switch(item.getItemId()){
        case R.id.Bearbeiten:
        EditText editText = (EditText) findViewById(R.id.editText);
            buttonActOne.setText(editText.getText());




            return true;
        case R.id.Löschen:
            return true;
            default:

    }

    return super.onContextItemSelected(item);


}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.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();

    //noinspection SimplifiableIfStatement
    if (id == R.id.action_settings) {
        return true;
    }

    return super.onOptionsItemSelected(item);


  }
}

当我启动程序并尝试编辑某些内容时，这是我的logcat日志。

08-28 13:52:06.135  26482-26482/com.example.michl.myapplication5 D/dalvikvm﹕ Late-enabling CheckJNI
08-28 13:52:06.150  26482-26488/com.example.michl.myapplication5 E/jdwp﹕ Failed sending reply to debugger: Broken pipe
08-28 13:52:06.150  26482-26488/com.example.michl.myapplication5 D/dalvikvm﹕ Debugger has detached; object registry had 1 entries
08-28 13:52:06.290  26482-26482/com.example.michl.myapplication5 D/libEGL﹕ loaded /system/lib/egl/libEGL_mali.so
08-28 13:52:06.295  26482-26482/com.example.michl.myapplication5 D/libEGL﹕ loaded /system/lib/egl/libGLESv1_CM_mali.so
08-28 13:52:06.295  26482-26482/com.example.michl.myapplication5 D/libEGL﹕ loaded /system/lib/egl/libGLESv2_mali.so
08-28 13:52:06.300  26482-26482/com.example.michl.myapplication5 D/﹕ Device driver API match
    Device driver API version: 10
    User space API version: 10
08-28 13:52:06.300  26482-26482/com.example.michl.myapplication5 D/﹕ mali: REVISION=Linux-r2p4-02rel0 BUILD_DATE=Thu Oct 25 08:43:05 KST 2012
08-28 13:52:06.315  26482-26482/com.example.michl.myapplication5 D/OpenGLRenderer﹕ Enabling debug mode 0
08-28 13:52:17.355  26482-26482/com.example.michl.myapplication5 I/dalvikvm﹕ Could not find method android.view.ViewGroup.onRtlPropertiesChanged, referenced from method android.support.v7.widget.Toolbar.onRtlPropertiesChanged
08-28 13:52:17.355  26482-26482/com.example.michl.myapplication5 W/dalvikvm﹕ VFY: unable to resolve virtual method 13334: Landroid/view/ViewGroup;.onRtlPropertiesChanged (I)V
08-28 13:52:17.355  26482-26482/com.example.michl.myapplication5 D/dalvikvm﹕ VFY: replacing opcode 0x6f at 0x0007
08-28 13:52:17.360  26482-26482/com.example.michl.myapplication5 I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getChangingConfigurations, referenced from method android.support.v7.internal.widget.TintTypedArray.getChangingConfigurations
08-28 13:52:17.360  26482-26485/com.example.michl.myapplication5 D/dalvikvm﹕ GC_CONCURRENT freed 188K, 14% free 9612K/11143K, paused 12ms+18ms, total 49ms
08-28 13:52:17.360  26482-26482/com.example.michl.myapplication5 W/dalvikvm﹕ VFY: unable to resolve virtual method 412: Landroid/content/res/TypedArray;.getChangingConfigurations ()I
08-28 13:52:17.360  26482-26482/com.example.michl.myapplication5 D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
08-28 13:52:17.360  26482-26482/com.example.michl.myapplication5 I/dalvikvm﹕ Could not find method android.content.res.TypedArray.getType, referenced from method android.support.v7.internal.widget.TintTypedArray.getType
08-28 13:52:17.360  26482-26482/com.example.michl.myapplication5 W/dalvikvm﹕ VFY: unable to resolve virtual method 434: Landroid/content/res/TypedArray;.getType (I)I
08-28 13:52:17.360  26482-26482/com.example.michl.myapplication5 D/dalvikvm﹕ VFY: replacing opcode 0x6e at 0x0002
08-28 13:52:17.465  26482-26482/com.example.michl.myapplication5 E/SpannableStringBuilder﹕ SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
08-28 13:52:17.465  26482-26482/com.example.michl.myapplication5 E/SpannableStringBuilder﹕ SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
08-28 13:52:18.345  26482-26482/com.example.michl.myapplication5 E/SpannableStringBuilder﹕ SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
08-28 13:52:18.345  26482-26482/com.example.michl.myapplication5 E/SpannableStringBuilder﹕ SPAN_EXCLUSIVE_EXCLUSIVE spans cannot have a zero length
08-28 13:52:19.605  26482-26482/com.example.michl.myapplication5 D/AbsListView﹕ Get MotionRecognitionManager
08-28 13:52:19.635  26482-26482/com.example.michl.myapplication5 W/ResourceType﹕ Failure getting entry for 0x010802c1 (t=7 e=705) in package 0 (error -75)
08-28 13:52:20.935  26482-26482/com.example.michl.myapplication5 D/AndroidRuntime﹕ Shutting down VM
08-28 13:52:20.935  26482-26482/com.example.michl.myapplication5 W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0x4191e2a0)
08-28 13:52:20.955  26482-26482/com.example.michl.myapplication5 E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.NullPointerException
            at com.example.michl.myapplication5.MainActivity.onContextItemSelected(MainActivity.java:161)
            at android.app.Activity.onMenuItemSelected(Activity.java:2647)
            at com.android.internal.policy.impl.PhoneWindow$DialogMenuCallback.onMenuItemSelected(PhoneWindow.java:3921)
            at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
            at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
            at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
            at com.android.internal.view.menu.MenuDialogHelper.onClick(MenuDialogHelper.java:193)
            at com.android.internal.app.AlertController$AlertParams$3.onItemClick(AlertController.java:934)
            at android.widget.AdapterView.performItemClick(AdapterView.java:301)
            at android.widget.AbsListView.performItemClick(AbsListView.java:1280)
            at android.widget.AbsListView$PerformClick.run(AbsListView.java:3071)
            at android.widget.AbsListView$1.run(AbsListView.java:3973)
            at android.os.Handler.handleCallback(Handler.java:615)
            at android.os.Handler.dispatchMessage(Handler.java:92)
            at android.os.Looper.loop(Looper.java:137)
            at android.app.ActivityThread.main(ActivityThread.java:4921)
            at java.lang.reflect.Method.invokeNative(Native Method)
            at java.lang.reflect.Method.invoke(Method.java:511)
            at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1027)
            at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:794)
            at dalvik.system.NativeStart.main(Native Method)
08-28 13:52:31.590  26482-26482/com.examp

le.michl.myapplication5 I/Process﹕ Sending signal. PID: 26482 SIG: 9

Answer 1

在Activity的onCreate方法上声明你的按钮！

Button buttonActOne = findViewById(R.id.buttonActOneId);

然后将侦听器添加到它：

buttonActOne.setOnClickListener(this); 

setOnClickListener实现了View.OnClickListener接口，所以@override方法必须是onClick（View v），然后在交换机中你可以使用v.getId（）;

简历中：

public class YourActivityName extends Activity implements View.OnClickListener {
    private Button buttonActOne;

    @Override
    public void onCreate(Bundle b) {
        //set your layout
        buttonActOne = findViewById(R.id.buttonActOneId); //put the id defined in your xml layout
    }

    @Override
    public void onClick(View view) {
        if (View.getId(R.id.Bearbeiten)) {
            EditText editText = (EditText) findViewById(R.id.editText);
            buttonActOne.setText(editText.getText());
        }
    }
}