Android_自定义View的三种实现方式

自定义控件的实现有三种方式，分别是：组合控件、继承控件和自绘控件

一:组合控件

1:新建一个Android项目，创建自定义的布局文件add_delete.xml

2:创建AddDelete类,继承RelativeLayout

本页面中主要是为自定义的标题栏加载了布局,为按钮添加事件监听方法,获取与修改EditText的方法

public class AddDelete extends RelativeLayout{

    private OnAddDeleteClickListener listener;
    private EditText ed_number;

    //对外提供一个点击的回调接口
    interface OnAddDeleteClickListener{
        void onAddClick(View v);
        void onDelClick(View v);
    }

    public void setOnAddDeleteClick(OnAddDeleteClickListener listener){
            this.listener = listener;
    }

    public AddDelete(Context context) {
        this(context,null);
    }

    public AddDelete(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }

    public AddDelete(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        intiView(context, attrs, defStyleAttr);
    }

    private void intiView(Context context, AttributeSet attrs, int defStyleAttr) {
        View.inflate(context,R.layout.adddelete,this);
        TextView add = (TextView)findViewById(R.id.add);
        TextView del = (TextView)findViewById(R.id.del);
        ed_number = (EditText) findViewById(R.id.ed_number);
        add.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                listener.onAddClick(view);
            }
        });
        del.setOnClickListener(new OnClickListener() {
            @Override
            public void onClick(View view) {
                listener.onDelClick(view);
            }
        });
    }
    //对外提供设置EditText值的方法
    public void setNumber(int number){
        //若果设置的值小于0则不设置
        if (number > 0) {
            ed_number.setText(number + "");
        }
    }
    //得到控件原来的值,并转成int类型
    public int getNumber(){
        int number = 0;
        try {
            //把值强转成int类型
            number = Integer.valueOf(ed_number.getText().toString().trim());
        }catch (Exception e){
            number = 0;
        }
        return number;
    }

}

3:在activity_main.xml中引入自定义的布局

4:MainActivity类

public class MainActivity extends AppCompatActivity {

    private AddDelete ad;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        //获取id
        ad = (AddDelete)findViewById(R.id.ad);
        //两个按钮的点击事件
        ad.setOnAddDeleteClick(new AddDelete.OnAddDeleteClickListener() {
            //增加EditText的值
            @Override
            public void onAddClick(View v) {
                int number = ad.getNumber();
                number++;
                ad.setNumber(number);
            }
            //减少EditText的值
            @Override
            public void onDelClick(View v) {
                int number = ad.getNumber();
                number--;
                ad.setNumber(number);
            }
        });

    }
}

二:继承控件

1:main_activity布局文件中写

2:创建MButton类,继承Button

public class MButton extends Button{

    public MButton(Context context) {
        this(context,null);
    }

    public MButton(Context context, AttributeSet attrs) {
        this(context, attrs,0);
    }

    public MButton(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        initView();
    }

    private void initView() {
        //为button设置背景颜色
        setBackgroundColor(Color.parseColor("#FF0000"));
    }
}

3:自绘控件
自绘控件的内容都是自己绘制出来的，在View的onDraw方法中完成绘制

1:main_activity布局文件中写

2:创建MyView类,继承View

public class MyView extends View{
    public MyView(Context context) {
        super(context);
    }

    public MyView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }

    public MyView(Context context, @Nullable AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }
    //自绘控件的内容都是自己绘制出来的，在View的onDraw方法中完成绘制,是最重要的方法
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
         int width = getWidth();
        int height = getHeight();


        // 绘图范围
        int react = Math.min(width, height);


        // 半径
        int radius = react / 2;


        // 绘制最外层的大圆
        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(Color.BLACK);
        paint.setAntiAlias(true);//消除锯齿
        paint.setStyle(Paint.Style.STROKE);


        canvas.drawCircle(radius, radius, radius, paint);


        // 画扇形
        paint.reset();
        paint.setStyle(Paint.Style.STROKE);
        paint.setStrokeWidth(20);
        paint.setColor(Color.GREEN);
        RectF rectF = new RectF();
        paint.setAntiAlias(true);//消除锯齿
        rectF.set(10, 10, react-10, react-10);
        canvas.drawArc(rectF, -90, progress*360/100, true, paint);


        // 画内层的小圆
        paint.reset();
        paint.setColor(Color.WHITE);
        paint.setAntiAlias(true);//消除锯齿
        paint.setStyle(Paint.Style.FILL_AND_STROKE);
        canvas.drawCircle(radius, radius, radius-20, paint);


        // 画进度文字
        paint.reset();
        paint.setColor(Color.BLUE);
        paint.setTextSize(40);
        Rect rect = new Rect();
        paint.getTextBounds(progress + "", 0, String.valueOf(progress).length(),
                rect);
        int textWidth = rect.width();
        int textHeight = rect.height();


        canvas.drawText(progress + "", radius-textWidth/2, radius-textHeight/2, paint);
    }
}

四:设置自定义view的属性

1:首先在values文件夹下创建attrs.xml

2:创建的类中

//R.styleable.上面declare-styleable标签的name

TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.Style);
        String left = typedArray.getString(R.styleable.Style_left);
        String middle = typedArray.getString(R.styleable.Style_middle);
        String right = typedArray.getString(R.styleable.Style_right);
        int color = typedArray.getColor(R.styleable.Style_color, Color.RED);
        控件id.setText(left);
        控件id.setText(middle);
        控件id.setText(right);
        控件id.setTextColor(color);
        //回收
        typedArray.recycle();

3:main_activity布局文件中写

    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" tools:context="activity.example.com.view.MainActivity">