Android Studio制作血条效果

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在Android Studio中制作血条可以通过自定义视图（Custom View）来实现。以下是一个简单的示例，展示如何使用自定义视图绘制一个简单的血条：

首先，在res/values/styles.xml文件中定义一个样式：

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<style name="HealthBar">
    <item name="android:layout_width">match_parent</item>
    <item name="android:layout_height">wrap_content</item>
    <item name="android:layout_margin">16dp</item>
    <item name="android:padding">4dp</item>
    <item name="android:background">@drawable/health_bar_background</item>
</style>

接下来，在res/drawable/health_bar_background.xml文件中定义血条的背景：

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<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:id="@android:id/background">
        <shape android:shape="rectangle">
            <solid android:color="#CCCCCC" /> <!-- Background color -->
            <corners android:radius="8dp" /> <!-- Corner radius -->
        </shape>
    </item>
    <item android:id="@android:id/progress">
        <clip>
            <shape android:shape="rectangle">
                <solid android:color="#FF0000" /> <!-- Progress color -->
                <corners android:radius="8dp" /> <!-- Corner radius -->
            </shape>
        </clip>
    </item>
</layer-list>

现在，创建一个自定义视图类HealthBarView，继承自View：

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import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

public class HealthBarView extends View {
    private Paint backgroundPaint;
    private Paint progressPaint;
    private float progress; // Progress value between 0 and 1

    public HealthBarView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    private void init() {
        backgroundPaint = new Paint();
        backgroundPaint.setColor(0xFFCCCCCC); // Background color
        progressPaint = new Paint();
        progressPaint.setColor(0xFFFF0000); // Progress color
    }

    public void setProgress(float progress) {
        this.progress = Math.max(0, Math.min(1, progress)); // Ensure progress is between 0 and 1
        invalidate(); // Request a redraw
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);

        // Draw background
        canvas.drawRect(0, 0, getWidth(), getHeight(), backgroundPaint);

        // Draw progress based on the current progress value
        float progressWidth = getWidth() * progress;
        canvas.drawRect(0, 0, progressWidth, getHeight(), progressPaint);
    }
}

在布局文件中使用自定义的HealthBarView：

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<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.example.yourapp.HealthBarView
        android:id="@+id/healthBar"
        style="@style/HealthBar"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintBottom_toBottomOf="parent" />

</RelativeLayout>

在代码中获取HealthBarView的实例并设置进度：

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HealthBarView healthBar = findViewById(R.id.healthBar);
healthBar.setProgress(0.7f); // Set progress to 70%

效果图