当我点击按钮我的应用程序崩溃

Question

当我点击我的按钮时，我的应用程序崩溃了。在log cat中它表示我不能解析“”（没有）

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



    ocjena1 = (EditText) findViewById(R.id.ocjena1);
    ocjena2 = (EditText) findViewById(R.id.ocjena2);
    ocjena3 = (EditText) findViewById(R.id.ocjena3);
    ocjena4 = (EditText) findViewById(R.id.ocjena4);
    ocjena5 = (EditText) findViewById(R.id.ocjena5);
    ocjena6 = (EditText) findViewById(R.id.ocjena6);
    ocjena7 = (EditText) findViewById(R.id.ocjena7);
    ocjena8 = (EditText) findViewById(R.id.ocjena8);
    ocjena9 = (EditText) findViewById(R.id.ocjena9);
    ocjena10 = (EditText) findViewById(R.id.ocjena10);
    ocjena11 = (EditText) findViewById(R.id.ocjena11);
    ocjena12 = (EditText) findViewById(R.id.ocjena12);
    ocjena13 = (EditText) findViewById(R.id.ocjena13);
    ocjena14 = (EditText) findViewById(R.id.ocjena14);
    ocjena15 = (EditText) findViewById(R.id.ocjena15);
    ocjena16 = (EditText) findViewById(R.id.ocjena16);
    ocjena17 = (EditText) findViewById(R.id.ocjena17);
    ocjena18 = (EditText) findViewById(R.id.ocjena18);
    ocjena19 = (EditText) findViewById(R.id.ocjena19);

    izracunaj = (Button) findViewById(R.id.izracunaj);

    prosjek = (TextView) findViewById(R.id.prosjekocjena);



         izracunaj.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
             b=0;
        if (ocjena1.getText().toString() != ""){
            a1 = Integer.parseInt( ocjena1.getText().toString() );
            b++;}else{a1=0;}

        if (ocjena2.getText().toString() != ""){
            a2 = Integer.parseInt( ocjena2.getText().toString() );
            b++;}else{a2=0;}

        if (ocjena3.getText().toString() != ""){
            a3 = Integer.parseInt( ocjena3.getText().toString() );
            b++;}else{a3=0;}

        if (ocjena4.getText().toString() != ""){
            a4 = Integer.parseInt( ocjena4.getText().toString() );
            b++;}else{a4=0;}

        if (ocjena5.getText().toString() != ""){
            a5 = Integer.parseInt( ocjena5.getText().toString() );
            b++;}else{a5=0;}

        if (ocjena6.getText().toString() != ""){
            a6 = Integer.parseInt( ocjena6.getText().toString() );
            b++;}else{a6=0;}

        if (ocjena7.getText().toString() != ""){
            a7 = Integer.parseInt( ocjena7.getText().toString() );
            b++;}else{a7=0;}

        if (ocjena8.getText().toString() != ""){
            a8 = Integer.parseInt( ocjena8.getText().toString() );
            b++;}else{a8=0;}

        if (ocjena9.getText().toString() != ""){
            a9 = Integer.parseInt( ocjena9.getText().toString() );
            b++;}else{a9=0;}

        if (ocjena10.getText().toString() != ""){
            a10 = Integer.parseInt( ocjena10.getText().toString() );
            b++;}else{a10=0;}

        if (ocjena11.getText().toString() != ""){
            a11 = Integer.parseInt( ocjena11.getText().toString() );
            b++;}else{a11=0;}

        if (ocjena12.getText().toString() != ""){
            a12 = Integer.parseInt( ocjena12.getText().toString() );
            b++;}else{a12=0;}

        if (ocjena13.getText().toString() != ""){
            a13 = Integer.parseInt( ocjena13.getText().toString() );
            b++;}else{a13=0;}

        if (ocjena14.getText().toString() != ""){
            a14 = Integer.parseInt( ocjena14.getText().toString() );
            b++;}else{a14=0;}

        if (ocjena15.getText().toString() != ""){
            a15 = Integer.parseInt( ocjena15.getText().toString() );
            b++;}else{a15=0;}

        if (ocjena16.getText().toString() != ""){
            a16 = Integer.parseInt( ocjena16.getText().toString() );
            b++;}else{a16=0;}

        if (ocjena17.getText().toString() != ""){
            a17 = Integer.parseInt( ocjena17.getText().toString() );
            b++;}else{a17=0;}

        if (ocjena18.getText().toString() != ""){
            a18 = Integer.parseInt( ocjena18.getText().toString() );
            b++;}else{a18=0;}

        if (ocjena19.getText().toString() != ""){
            a19 = Integer.parseInt( ocjena19.getText().toString() );
            b++;}else{a19=0;}
        double rez = (a1+a2+a3+a4+a5+a6+a7+a8+a9+a10+a11+a12+a13+a14+a15+a16+a17+a18+a19)/b;
        String rezString= Double.toString(rez);
        prosjek.setText(rezString);


        }});

     }







@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;
    }
}

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

}

Answer 1

请勿使用==或!=进行字符串比较。您正在比较对象引用而不是值。

使用equals()，或者与""，isEmpty()进行比较。

Answer 2

使用

if (!ocjena1.getText().toString().equals(""))

而不是

if (ocjena1.getText().toString() != "")