在弹出窗口中更改文本视图的文本时遇到问题。
简单版本的代码如下所示：
public class Activity extends Activity {
View popupView;
PopupWindow pw_info;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
this.requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_menue);
// Layout components
tv_function = (TextView) findViewById(R.id.function);
tv_result = (TextView) findViewById(R.id.tv_result);
tv_total = (TextView) findViewById(R.id.tv_total_result);
});
@Override
protected void onStart(){
super.onStart();
pop_up();
}
// PopUp Window for start and end
private void pop_up(){
LayoutInflater layoutInflater = (LayoutInflater) getBaseContext().getSystemService(LAYOUT_INFLATER_SERVICE);
popupView = layoutInflater.inflate(R.layout.popup_window, null);
final PopupWindow pw_popupWindow = new PopupWindow(popupView, LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT);
popupView.post(new Runnable() {
public void run() {
pw_popupWindow.showAtLocation(popupView, Gravity.CENTER, 0, 0);
tv_function.setText("start");
tv_popup = (TextView) findViewById(R.id.tv_popup_text);
new CountDownTimer(3000, 1000) {
public void onTick(long l_millisUntilFinished) {
// Problem: accessing tv_popup creates NULLPOINTER Exception!
tv_popup.setText(String.valueOf(l_millisUntilFinished / 1000));
}
public void onFinish() {
pw_popupWindow.dismiss();
}
}.start();
}
});
}
我尝试在倒计时的每个滴答声中更改 TextView。我的问题是我无法在倒计时期间更改 TextView。这会导致 NullPointer 异常。我不确定何时定义和初始化tv_popupTextView。
有人能帮忙吗？
谢谢！