Null指针在检查Dialog中的复选框后尝试将项添加到SQLiteDataBase

时间：2014-01-07 22:17:51

标签： android checkbox nullpointerexception android-sqlite onclicklistener

我遇到了一个复选框问题，并在Sql中向数据库添加项目。问题是我在第171行得到一个空指针异常，即：

    db.addTimer(new TimerClass(tagval1, String.valueOf(startTime*60)));

此条目基本上是以下行的镜像，如果现在已创建，我将使用该镜像向数据库添加默认值：

    db.addTimer(new TimerClass("Lipton", "180"));

表示我要检查以触发第一行的复选框值是在下面列出的显示对话框代码中设置的：

    public void showDialog(){
    cusd = new Dialog(MainActivity.this,R.style.Theme_MultiTimer_Dialog);
    cusd.setContentView(R.layout.dialogbox);
    canlbtn = (Button) cusd.findViewById(R.id.cancelbtn);
    sbtbtn = (Button) cusd.findViewById(R.id.submitbtn);        
    minnp = (NumberPicker) cusd.findViewById(R.id.numberPicker1);
    secnp = (NumberPicker) cusd.findViewById(R.id.numberPicker2);
    tagvalue = (EditText) cusd.findViewById(R.id.tagname);
    ckb = (CheckBox) cusd.findViewById(R.id.savecheckBox);
    ckb.setOnClickListener(this);
    canlbtn.setOnClickListener(this);
    sbtbtn.setOnClickListener(this);
    minnp.setMaxValue(59);
    minnp.setMinValue(0);
    minnp.setWrapSelectorWheel(false);
    minnp.setOnValueChangedListener(this);
    secnp.setMaxValue(59);
    secnp.setMinValue(0);
    secnp.setWrapSelectorWheel(false);
    secnp.setOnValueChangedListener(this);
    cusd.show();
}

现在我在同一个对话框中还有两（2）个数字选择器和一个EditText，我可以舒适地提取值。问题是当我尝试将条目添加到数据库本身时。下面是addtimer代码，它是添加到数据库的通用代码，如上所述，它可以很方便地使用我上面列出的第二行代码。

       public void addTimer(TimerClass timers){
    SQLiteDatabase db = this.getWritableDatabase();
    ContentValues values = new ContentValues();
    values.put(KEY_TAG, timers.getTag());
    values.put(KEY_TIMEINSECONDS, timers.gettimeInSeconds());
    db.insert(TABLE_NAME, null, values);
    db.close();
}

请参阅下面我宣布必要项目的地方以及我实例化不同代码的代码。

    public class MainActivity extends Activity implements NumberPicker.OnValueChangeListener, OnClickListener, OnItemSelectedListener{
//--------------------------------------------------------------------------------------------------
Button dgbtn, abbtn, exbtn, canlbtn, sbtbtn, starest, clrbtn, deltbtn;
EditText tagvalue;
TextView timeRemaining, titleTvRight, titleTvLeft;
NumberPicker minnp, secnp;
Dialog cusd;
ProgressBar titleProgressBar;
TimerDataBaseHandler db;
Spinner s;
CheckBox ckb;
protected CountDownTimer timerCountDownTimer;
private boolean timerHasStarted = false;
private TextView timeElapsedView;
protected int startTime=0;
protected int val1, val2, val3, val4;
protected String tagval1;
boolean customTitleSupported, savechkbx;
File mydb ;
//--------------------------------------------------------------------------------------------------
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    customTitleSupported= requestWindowFeature(Window.FEATURE_CUSTOM_TITLE);
    setContentView(R.layout.main);
    getWindow().setFeatureInt(Window.FEATURE_CUSTOM_TITLE, R.layout.custom_title);
    TimerDataBaseHandler db = new TimerDataBaseHandler(getApplicationContext());
    mydb = new File("/data/data/com.vertygoeclypse.multitimer/databases/TimerManager");
    if(mydb.exists()){
        Log.i("VertygoEclypse", "True");
    } else {
        Log.i("VertygoEclypse", "false");
        db.addTimer(new TimerClass("Lipton", "180"));
    }
//--------------------------------------------------------------------------------------------------
    dgbtn = (Button) findViewById(R.id.dialogbtn);
    abbtn = (Button) findViewById(R.id.aboutbtn);
    exbtn = (Button) findViewById(R.id.exitbtn);
    starest =  (Button) findViewById(R.id.startresetbtn);
    clrbtn = (Button) findViewById(R.id.clearvaluesbutton);
    deltbtn = (Button)     findViewById(R.id.deletevaluesbutton);
    timeRemaining = (TextView) findViewById(R.id.timeremainingview);
    titleTvLeft = (TextView)findViewById(R.id.titleTVLeft);
    titleTvRight = (TextView)findViewById(R.id.titleTVRight);
    titleProgressBar = (ProgressBar)findViewById(R.id.leadprogressBar);
    s = (Spinner)findViewById(R.id.timerspinner);
//--------------------------------------------------------------------------------------------------
    dgbtn.setOnClickListener(this);
    abbtn.setOnClickListener(this);
    exbtn.setOnClickListener(this);
    starest.setOnClickListener(this);
    clrbtn.setOnClickListener(this);
    deltbtn.setOnClickListener(this);
    s.setOnItemSelectedListener(this);

任何人都可以帮忙解决这个问题，我确信这个问题是我缺少的，但是对于Android编程很新，我想我看不到它。

另请参阅下面的logcat捕获，我在那里指出第171行作为问题的位置。

    01-07 21:58:49.650    1971-1971/com.vertygoeclypse.multitimer I/VertygoEclypse﹕ True
    01-07 21:58:49.678    1971-1971/com.vertygoeclypse.multitimer D/dalvikvm﹕ GC_FOR_ALLOC freed 74K, 10% free 2906K/3212K, paused 3ms, total 3ms
    01-07 21:58:49.698    1971-1971/com.vertygoeclypse.multitimer D/libEGL﹕ loaded /system/lib/egl/libEGL_genymotion.so
    01-07 21:58:49.698    1971-1971/com.vertygoeclypse.multitimer D/﹕ HostConnection::get() New Host Connection established 0xb8db9bf0, tid 1971
    01-07 21:58:49.710    1971-1971/com.vertygoeclypse.multitimer D/libEGL﹕ loaded /system/lib/egl/libGLESv1_CM_genymotion.so
    01-07 21:58:49.710    1971-1971/com.vertygoeclypse.multitimer D/libEGL﹕ loaded /system/lib/egl/libGLESv2_genymotion.so
    01-07 21:58:49.774    1971-1971/com.vertygoeclypse.multitimer W/EGL_genymotion﹕ eglSurfaceAttrib not implemented
    01-07 21:58:49.774    1971-1971/com.vertygoeclypse.multitimer E/OpenGLRenderer﹕ Getting MAX_TEXTURE_SIZE from GradienCache
    01-07 21:58:49.782    1971-1971/com.vertygoeclypse.multitimer E/OpenGLRenderer﹕ Getting MAX_TEXTURE_SIZE from Caches::initConstraints()
    01-07 21:58:49.782    1971-1971/com.vertygoeclypse.multitimer D/OpenGLRenderer﹕ Enabling debug mode 0
    01-07 21:59:22.058    1971-1971/com.vertygoeclypse.multitimer D/dalvikvm﹕ GC_FOR_ALLOC freed 44K, 8% free 3327K/3612K, paused 7ms, total 7ms
    01-07 21:59:22.070    1971-1971/com.vertygoeclypse.multitimer D/dalvikvm﹕ GC_FOR_ALLOC freed 15K, 8% free 3715K/4028K, paused 2ms, total 2ms
    01-07 21:59:22.154    1971-1971/com.vertygoeclypse.multitimer W/EGL_genymotion﹕ eglSurfaceAttrib not implemented
    01-07 21:59:22.238    1971-1971/com.vertygoeclypse.multitimer V/RenderScript﹕ 0xb8eb9850 Launching thread(s), CPUs 4
    01-07 21:59:23.826    1971-1971/com.vertygoeclypse.multitimer D/dalvikvm﹕ GC_FOR_ALLOC freed 60K, 7% free 4167K/4460K, paused 1ms, total 2ms
    01-07 21:59:27.154    1971-1971/com.vertygoeclypse.multitimer D/AndroidRuntime﹕ Shutting down VM
    01-07 21:59:27.154    1971-1971/com.vertygoeclypse.multitimer W/dalvikvm﹕ threadid=1: thread exiting with uncaught exception (group=0xa4bee648)
    01-07 21:59:27.158    1971-1971/com.vertygoeclypse.multitimer E/AndroidRuntime﹕ FATAL EXCEPTION: main
    java.lang.NullPointerException
        at com.vertygoeclypse.multitimer.MainActivity.onClick(MainActivity.java:171)
        at android.view.View.performClick(View.java:4240)
        at android.view.View$PerformClick.run(View.java:17721)
        at android.os.Handler.handleCallback(Handler.java:730)
        at android.os.Handler.dispatchMessage(Handler.java:92)
        at android.os.Looper.loop(Looper.java:137)
        at android.app.ActivityThread.main(ActivityThread.java:5103)
        at java.lang.reflect.Method.invokeNative(Native Method)
        at java.lang.reflect.Method.invoke(Method.java:525)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
        at dalvik.system.NativeStart.main(Native Method)

提前感谢所有能帮助我的人，感谢您的时间和精力。

问候

cchinchoy

1 个答案:

答案 0 :(得分：1)

经过大量的代码试验和错误后，解决方案才出现。我意识到复选框的代码是错误的，并且：

    ckb.setOnClickListener(this);

进入这个：

    ckb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener()

这样做会带来以下几点：

            ckb.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() {
        @Override
        public void onCheckedChanged(CompoundButton compoundButton, boolean isChecked) {
            if(isChecked){
                savechkbx = true;
            } else {
                savechkbx = false;
            }
        }
    });

我已经将savechkbx的声明创建为布尔值，然后将其设置为false。这是为了抵消我在xml文件中将复选框设置为true的事实，如下所示：

        <CheckBox
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_marginLeft="20sp"
    android:layout_marginRight="5sp"
    android:layout_marginTop="1sp"
    android:text="Saver Timer for Later use!!!"
    android:id="@+id/savecheckBox"
    android:checked="true" >
    </CheckBox>

据说那就是在提交按钮检查中，我有以下内容：

            if(savechkbx==true){
            db.addTimer(new TimerClass(tagval1, temp2));
             }

否则它什么都不返回。我必须修改代码，使其更清洁。这解决了这个问题。

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