java - 旋转屏幕时如何保存可绘制的按钮

Question

我刚读到:Saving Android Activity state using Save Instance State

这个:Android - Open resource from @drawable String

我的情况是:我有一个 Button 背景设置，当按下它时它变成绿色

button.setBackgroundResource(R.drawable.greenbutton);

如何使用 onSaveInstanceState 和 onRestoreInstanceState 存储此信息？

我试过:How to maintain a button style and click state after screen rotation? 并且有效 但也许还有比三嵌套 if 条件过程更好的东西？我的意思是我必须为 4+ Button 做这件事，我认为这只是一个简单的原因:)

谢谢

编辑:这是目前为止的代码

package com.example.android.testbutton;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.Button;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        button = (Button) findViewById(R.id.change);
    }

    Button button;
    Boolean click;

    public void changeColor(View view) {
        click = true;
        button.setBackgroundResource(R.drawable.greenbutton);
    }


    @Override
    public void onSaveInstanceState(Bundle savedInstanceState) {

        // Save UI state changes to the savedInstanceState.
        // This bundle will be passed to onCreate if the process is
        // killed and restarted.

        savedInstanceState.putBoolean("buttonClicked", click);
        // etc.

        super.onSaveInstanceState(savedInstanceState);
    }

//onRestoreInstanceState

    @Override
    public void onRestoreInstanceState(Bundle savedInstanceState) {

        super.onRestoreInstanceState(savedInstanceState);

        // Restore UI state from the savedInstanceState.
        // This bundle has also been passed to onCreate.

        Boolean firstAnswer = savedInstanceState.getBoolean("buttonClicked");
        {
            if (savedInstanceState != null) {
                if (savedInstanceState.containsKey("buttonClicked")) {
                    if (savedInstanceState.getBoolean("buttonClicked"))
                        button.setBackgroundResource(R.drawable.greenbutton);

                    //some codes to make the button becomes clicked.
                }
            }
        }
    }
}

Answer 1

也为您的 Activity 设置一个变量，然后保存并使用您的状态恢复它。

public class MyActivity extends Activity {

public static final String KEY_BUTTON_IS_GREEN = "isGreen";
boolean buttonIsGreen;

@Override
protected void onSaveInstanceState(Bundle outState) {
    outState.putBoolean(KEY_BUTTON_IS_GREEN, buttonIsGreen);
    super.onSaveInstanceState(outState);
}

@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
    super.onRestoreInstanceState(savedInstanceState);
    buttonIsGreen = savedInstanceState.getBoolean(KEY_BUTTON_IS_GREEN, false);
    if (buttonIsGreen){
        // find the button and set it green.
    }
}

您需要添加将按钮设置为绿色的方法，如果按钮为绿色，还需要设置您的变量 = true。