Question

我对android很新，这是我第一天这样做。我正在创建这个有2个按钮的应用程序，负责在按下后更改布局的颜色。按下按钮时，我使用Toast类显示一条消息，说明颜色已更改。 但我希望逻辑能够使特定按钮的toast消息只显示一次，而不是后续按下相同按钮。为此，我使用了一个布尔标志，只要按钮是单击，将布尔变量更改为false，然后不显示Toast消息。但是这个逻辑存在问题。该应用程序不会显示toast消息以供将来点击使用。我真的很感激，如果有人能帮助我一点点这个逻辑，那么应用程序会知道足够聪明，可以处理未来的印刷机。

public class MainActivity extends AppCompatActivity {
    private Button myblue_button;
    private Button mygreen_button;
    private LinearLayout backGround;
    private TextView textArea;
    boolean forBLue = true;
    boolean forGreen = true;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    textArea = (TextView) findViewById(R.id.textID); //id for text area to later change it
    backGround = (LinearLayout) findViewById(R.id.linearlayoutID);
    myblue_button = (Button) findViewById(R.id.blue_button);
    myblue_button.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View view) {
            backGround.setBackgroundColor(getResources().getColor(android.R.color.holo_blue_bright));
            textArea.setText("Now we feel blue");
            if (forBLue == true){
                Toast.makeText(MainActivity.this,"Now we feel blue",Toast.LENGTH_SHORT).show();
                forBLue = false;
            }
        }
    });

    mygreen_button = (Button) findViewById(R.id.green_button);
    mygreen_button.setOnClickListener(new OnClickListener() {
        @Override
        public void onClick(View view) {
            backGround.setBackgroundColor(getResources().getColor(android.R.color.holo_green_light));
            textArea.setText("Now we feel green");
            if (forGreen == true) {
                Toast.makeText(MainActivity.this, "Now we feel green", Toast.LENGTH_SHORT).show();
                forGreen = false;
            }
        }
    });
}
}

以下是XML文件

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/linearlayoutID"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
>

<TextView
    android:id = "@+id/textID"
    android:text="Click the button that best represents your mood"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_gravity="center"
    />
<LinearLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal"

    >
<Button
    android:id="@+id/blue_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="BLUE"
    android:layout_weight="1"
    />
<Button
    android:id="@+id/green_button"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="GREEN"
    android:layout_weight="1"
    />
</LinearLayout>>

Answer 1

private int blue, green = 0;

myblue_button.setOnClickListener(new View.OnClickListener(){
            @Override
            public void onClick(View view) {
                backGround.setBackgroundColor(getResources().getColor(android.R.color.holo_blue_bright));
                textArea.setText("Now we feel blue");
                if (blue == 0){
                    Toast.makeText(MainActivity.this,"Now we feel blue",Toast.LENGTH_SHORT).show();
                    blue = 1;
                    green = 0;
                }
            }
        });

        mygreen_button.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                backGround.setBackgroundColor(getResources().getColor(android.R.color.holo_green_light));
                textArea.setText("Now we feel green");
                if (green == 0) {
                    Toast.makeText(MainActivity.this, "Now we feel green", Toast.LENGTH_SHORT).show();
                    green = 1;
                    blue = 0;
    }
            }
        });
    }
    }

这是一个可以解决问题的代码。

Answer 2

你需要这样做：

if (forBLue == true){
                Toast.makeText(MainActivity.this,"Now we feel blue",Toast.LENGTH_SHORT).show();
                forBLue = false;
                forGreen = true ;//edit here
            }

和：

if (forGreen == true) {
                Toast.makeText(MainActivity.this, "Now we feel green", Toast.LENGTH_SHORT).show();
                forGreen = false;
                forBlue = true;//edit here
            }

Answer 3

这样做：

boolean shouldShowToastOnBlue = true;
boolean shouldShowToastOnGreen = true;

...

myblue_button.setOnClickListener(new View.OnClickListener(){
    @Override
    public void onClick(View view) {
        backGround.setBackgroundColor(getResources().getColor(android.R.color.holo_blue_bright));
        textArea.setText("Now we feel blue");
        if (shouldShowToastOnBlue){
            Toast.makeText(MainActivity.this,"Now we feel blue",Toast.LENGTH_SHORT).show();
            shouldShowToastOnBlue = false;
        }
        shouldShowToastOnGreen = true;
    }
});

mygreen_button = (Button) findViewById(R.id.green_button);
mygreen_button.setOnClickListener(new OnClickListener() {
    @Override
    public void onClick(View view) {
        backGround.setBackgroundColor(getResources().getColor(android.R.color.holo_green_light));
        textArea.setText("Now we feel green");
        if (shouldShowToastOnGreen) {
            Toast.makeText(MainActivity.this, "Now we feel green", Toast.LENGTH_SHORT).show();
            shouldShowToastOnGreen = false;
        }
        shouldShowToastOnBlue = true;
    }
});

对于后续按下，使按钮仅显示Toast消息一次

3 个答案: