android绘制一个条形图

以下是一个简单的Android条形图绘制示例：

1. 创建一个新的Android项目并在布局文件中添加一个FrameLayout，用于显示条形图。

2. 在Java代码中，编写以下代码来绘制条形图：

public class BarChartView extends View {
    private Paint mPaint;
    private ArrayList<Bar> mBars = new ArrayList<Bar>();

    public BarChartView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mPaint = new Paint();
        mPaint.setColor(Color.BLUE);
    }

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

        int canvasWidth = canvas.getWidth();
        int canvasHeight = canvas.getHeight();

        // 绘制条形图背景
        mPaint.setColor(Color.LTGRAY);
        canvas.drawRect(0, 0, canvasWidth, canvasHeight, mPaint);

        // 计算每个条形的宽度
        int barCount = mBars.size();
        int barWidth = canvasWidth / barCount;

        // 绘制每个条形
        for (int i = 0; i < barCount; i++) {
            Bar bar = mBars.get(i);
            int barHeight = (int) ((float) bar.value / 100 * canvasHeight);
            int left = i * barWidth;
            int right = left + barWidth;
            int bottom = canvasHeight;
            int top = canvasHeight - barHeight;
            canvas.drawRect(left, top, right, bottom, mPaint);
        }
    }

    public void addBar(Bar bar) {
        mBars.add(bar);
        invalidate();
    }

    public static class Bar {
        public String label;
        public int value;

        public Bar(String label, int value) {
            this.label = label;
            this.value = value;
        }
    }
}

3. 在Activity中，实例化BarChartView并添加条形：

public class MainActivity extends AppCompatActivity {
    private BarChartView mBarChartView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        mBarChartView = findViewById(R.id.bar_chart_view);

        mBarChartView.addBar(new BarChartView.Bar("Bar 1", 50));
        mBarChartView.addBar(new BarChartView.Bar("Bar 2", 75));
        mBarChartView.addBar(new BarChartView.Bar("Bar 3", 25));
        mBarChartView.addBar(new BarChartView.Bar("Bar 4", 90));
        mBarChartView.addBar(new BarChartView.Bar("Bar 5", 60));
    }
}

4. 运行应用程序，应该会显示一个包含五个条形的条形图。