onSaveInstanceState 不起作用 [英] onSaveInstanceState not working

问题描述

我知道这个问题已经被问了很多，但我不明白为什么 onSaveInstanceState 对我不起作用.这可能是一些愚蠢的事情，但我希望你们中的一些人可以在这里帮助我.无论如何，这是我的代码:

I know this question has already been asked a lot, but I don't get why onSaveInstanceState isn't working for me. It's probably something stupid, but I hope some of you can help me out here.. Anyways, this is my code:

public class Main extends Activity implements OnClickListener, OnKeyListener {

EditText textitem;
Button buttonadd;
ListView listitems;

ArrayList<String> ToDo;
ArrayAdapter<String> AA;
ArrayList<String> MyArrayList;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    textitem = (EditText) findViewById(R.id.textitem);
    buttonadd = (Button) findViewById(R.id.buttonadd);
    listitems = (ListView) findViewById(R.id.listitems);

    buttonadd.setOnClickListener(this);
    textitem.setOnKeyListener(this);

    ToDo = new ArrayList<String>();
    AA = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, ToDo);
    listitems.setAdapter(AA);

}

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
    savedInstanceState.putStringArrayList("MyArrayList", ToDo);
    super.onSaveInstanceState(savedInstanceState);
}

@Override
public void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    ArrayList<String> ToDo = savedInstanceState.getStringArrayList("MyArrayList");
}

private void addItem(String item) {
    if (item.length() > 0) {
        this.ToDo.add(item);
        this.AA.notifyDataSetChanged();
        this.textitem.setText("");
    }
}

public void onClick(View v) {
    if (v == this.buttonadd) {
        this.addItem(this.textitem.getText().toString());
    }
}

public boolean onKey(View v, int keyCode, KeyEvent event) {
    if (event.getAction() == KeyEvent.ACTION_DOWN
            && keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
        this.addItem(this.textitem.getText().toString());
    }
    return false;
}

}

推荐答案

public class Main extends Activity implements OnClickListener, OnKeyListener {

EditText textitem;
Button buttonadd;
ListView listitems;

ArrayList<String> ToDo;
ArrayAdapter<String> AA;
ArrayList<String> MyArrayList;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    textitem = (EditText) findViewById(R.id.textitem);
    buttonadd = (Button) findViewById(R.id.buttonadd);
    listitems = (ListView) findViewById(R.id.listitems);

    buttonadd.setOnClickListener(this);
    textitem.setOnKeyListener(this);

    if(savedInstanceState!=null)
     {
       ToDo = savedInstanceState.getStringArrayList("MyArrayList");
     }
    else
     {
       ToDo = new ArrayList<String>();
     }
    AA = new ArrayAdapter<String>(this,
            android.R.layout.simple_list_item_1, ToDo);
    listitems.setAdapter(AA);

}

@Override
public void onSaveInstanceState(Bundle savedInstanceState) {
    savedInstanceState.putStringArrayList("MyArrayList", ToDo);
    super.onSaveInstanceState(savedInstanceState);
}


private void addItem(String item) {
    if (item.length() > 0) {
        this.ToDo.add(item);
        this.AA.notifyDataSetChanged();
        this.textitem.setText("");
    }
}

public void onClick(View v) {
    if (v == this.buttonadd) {
        this.addItem(this.textitem.getText().toString());
    }
}

public boolean onKey(View v, int keyCode, KeyEvent event) {
    if (event.getAction() == KeyEvent.ACTION_DOWN
            && keyCode == KeyEvent.KEYCODE_DPAD_CENTER) {
        this.addItem(this.textitem.getText().toString());
    }
    return false;
}

希望这会对您有所帮助.维普尔

Hope this will help you. Vipul

这篇关于onSaveInstanceState 不起作用的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！