Question

我创建了一个按钮并通过执行

将其指定为1

remove.setId(0 + count);

然后我尝试将该按钮放在我的onCreate包中以使用它

Button remove = (Button)findViewById(1);

remove.setOnClickListener(new View.OnClickListener() {

    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub

    }
});

当我创建按钮时，在我的oncreate中删除它会运行但是只要我添加我的onclick监听器我就不会收到任何错误但是当我运行它时它强制关闭

日志

12-12 13:42:06.172: D/AndroidRuntime(19502): Shutting down VM
12-12 13:42:06.172: W/dalvikvm(19502): threadid=1: thread exiting with uncaught exception (group=0x416bbd40)
12-12 13:42:06.178: E/AndroidRuntime(19502): FATAL EXCEPTION: main
12-12 13:42:06.178: E/AndroidRuntime(19502): Process: com.th3ramr0d.armytrooptotask, PID: 19502
12-12 13:42:06.178: E/AndroidRuntime(19502): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.th3ramr0d.armytrooptotask/com.th3ramr0d.armytrooptotask.MainActivity}: java.lang.NullPointerException
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2209)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2269)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.app.ActivityThread.access$800(ActivityThread.java:139)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1210)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.os.Handler.dispatchMessage(Handler.java:102)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.os.Looper.loop(Looper.java:136)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.app.ActivityThread.main(ActivityThread.java:5102)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at java.lang.reflect.Method.invokeNative(Native Method)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at java.lang.reflect.Method.invoke(Method.java:515)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at dalvik.system.NativeStart.main(Native Method)
12-12 13:42:06.178: E/AndroidRuntime(19502): Caused by: java.lang.NullPointerException
12-12 13:42:06.178: E/AndroidRuntime(19502):    at com.th3ramr0d.armytrooptotask.MainActivity.onCreate(MainActivity.java:45)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.app.Activity.performCreate(Activity.java:5248)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1110)
12-12 13:42:06.178: E/AndroidRuntime(19502):    at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2173)
12-12 13:42:06.178: E/AndroidRuntime(19502):    ... 11 more

这是我的完整档案

package com.th3ramr0d.armytrooptotask;

import android.app.Activity;
import android.app.AlertDialog;
import android.content.DialogInterface;
import android.os.Bundle;
import android.text.Editable;
import android.view.Gravity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.ViewGroup.LayoutParams;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.Toast;

public class MainActivity extends Activity {

public int count = 1;

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

    Button addTroopBtn = (Button) findViewById(R.id.addTroop);

    addTroopBtn.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub
            if(count <= 5)
            {
            inputName(v);
            }
            else
            {

            }
        }
    });

    Button remove = (Button)findViewById(1);

    remove.setOnClickListener(new View.OnClickListener() {

        @Override
        public void onClick(View v) {
            // TODO Auto-generated method stub

        }
    });
}

public void inputName(final View v){
    AlertDialog.Builder alert = new AlertDialog.Builder(this);

    //alert.setTitle("Enter Name and Rank");
    alert.setMessage("Please Enter A Name");

    // Set an EditText view to get user input 
    final EditText input = new EditText(this);
    alert.setView(input);

    alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
    public void onClick(DialogInterface dialog, int whichButton) {
      Editable name = input.getText();
      addTroop(name);
      }
    });

    alert.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
      public void onClick(DialogInterface dialog, int whichButton) {
        // Canceled.
      }
    });

    alert.show();
}

public void addTroop(Editable name){

    LinearLayout mainPage = (LinearLayout) findViewById(R.id.manageTroopsMain);

    if (count <= 5)
    {
    //CREATE NEW LINEAR LAYOUT
    LinearLayout addTroopLayout = new LinearLayout(this);   

    //CREATE LAYOUT PARAMS FOR LAYOUT
    LinearLayout.LayoutParams newLayout = new LinearLayout.LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);
    newLayout.bottomMargin = 10;

    //STYLE NEW LINEAR LAYOUT
    addTroopLayout.setTag("addTroopLayout" + count);
    addTroopLayout.setLayoutParams(newLayout);
    addTroopLayout.setOrientation(LinearLayout.HORIZONTAL);     

    //CREATE NEW BUTTONS
    Button newTroop = new Button(this);
    Button remove = new Button(this);
    Button change = new Button(this);

    //CREATE LAYOUT PARAMS FOR BUTTONS
    LinearLayout.LayoutParams newTroopParam = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, 20f);
    LinearLayout.LayoutParams rmvBtnParam = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, .5f);
    LinearLayout.LayoutParams chngNameParam = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT, .5f);


    //STYLE NEW BUTTONS
    newTroop.setText(name);
    newTroop.setGravity(Gravity.LEFT|Gravity.CENTER_VERTICAL);
    newTroop.setLayoutParams(newTroopParam);
    remove.setId(0 + count);
    remove.setText("-");
    remove.setGravity(Gravity.CENTER_HORIZONTAL|Gravity.CENTER_VERTICAL);
    remove.setLayoutParams(rmvBtnParam);
    change.setText("...");
    change.setGravity(Gravity.CENTER_HORIZONTAL|Gravity.CENTER_VERTICAL);
    change.setLayoutParams(chngNameParam);

    //ADD VIEWS TO NEW LAYOUT
    addTroopLayout.addView(newTroop);
    addTroopLayout.addView(remove);
    addTroopLayout.addView(change);

    //ADD NEW LAYOUT TO mainPage LAYOUT
    mainPage.addView(addTroopLayout);

    //Increment Counter
    count++;
    }
}

}

Answer 1

这是你的问题：按钮删除=（按钮）findViewById（1）;

这应该是这样的：

Button remove = (Button)findViewById(R.id.buttonRemove);   // that should be a long int

Answer 2

崩溃可能发生在这条线上：

Button remove = (Button)findViewById(1);

您需要在充气布局中为Button提供有效的ID。值1没有意义。

设置onclick时强制关闭

2 个答案: