我创建了一个按钮并通过执行
将其指定为1remove.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++;
}
}
}
答案 0 :(得分：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
答案 1 :(得分：0)
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。