行Txt_EarnedPoint.getText（）抛出Nullpointer异常（textview） - Eclipse for Android

Question

在Txt_EarnedPoint.getText（）行中它抛出Nullpointer异常为什么？ Txt_EarnedPoint是一个textview。如果我删除该行，每个想法都可以。 Plz帮帮我......

        public class MainActivity extends ActionBarActivity implements
            android.view.View.OnClickListener {
         private TextView Txt_EarnedPoint;
         private Button saveButton;
         private Button DisableBtn;
         private Button selectbutton;

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


            TextView  Txt_EarnedPoint=(TextView ) findViewById(R.id.textView1);
    public void GetImageId(int Imageid) {
            else if (count == 1
                            && CheckBtnText == selectbutton.getText().toString()) {
                        selectbutton.setBackgroundResource(selectAptImage);
                        selectbutton.setEnabled(false);
                        count = 0;
                        IncCounter += 1;
                        saveButton.setText("0");
                        selectbutton.setText("0");
--error part----------->Txt_EarnedPoint.getText();
                        if (IncCounter == 6) {
                            AlertDialog d = new AlertDialog.Builder(this)

                                    .setTitle("Completed Level 1")
                                    .setMessage("Level Completed")
                                    .setPositiveButton("Why should I stop Playing?", null)
                                    .setNegativeButton("Tired to go on", null).show();
                            HideAllButton();
                        }
    }
    }

Answer 1

您没有创建对象并将其分配给实例成员，而是创建了一个被遗忘的局部变量＆＃39;当onCreate完成执行时。

更改行：

TextView Txt_EarnedPoint=(TextView ) findViewById(R.id.textView1);

要：

Txt_EarnedPoint=(TextView ) findViewById(R.id.textView1);