Android_自定义View-和view的监听事件

1.自定义view当作标签配置时，必须加上包名

2.反射方式创建UI组件对象时，使用的构造方法为下面两个构造方式之一

View(Context context, AttributeSet attrs)：

View(Context context, AttributeSet attrs, int defStyle)：
View(Context context)

1 自定义View要学习的是重写3个方法， 写构造方法

（1）onDraw
（2）onMeasure
（3）onLayout

2.自定义View的构造方法和onDraw

3.自定义view在布局文件中使用时，必须把包名加上

<xena.view.MyView
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:background="#ff00ffff"
        />
调用的构造方法是MyView(Context context, AttributeSet attrs)

4.view.invalidate();//触发onDraw方法的执行

5.onMeasure

6.得到View的宽高

 view.getMeasuredHeight();// 得到view的高
 view.getMeasuredWidth();//  得到view的宽

DisplayMetrics dm = new DisplayMetrics();
activity.getWindowManager().getDefaultDisplay().getMetrics(dm);
int screenW = dm.widthPixels;//这就是屏的宽
int screenH = dm.heightPixels;

自定义view写文字“中华人民共和国”

<pre name="code" class="java"><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >

<Button
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="确定" />

<test.act.MyTextView
android:paddingLeft="40dp"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />

</LinearLayout>

<pre name="code" class="java">public class MyTextView extends View {
private String text = "中华人民共和国";
private int textSize = 100;
private Context context;
private int textColor = Color.RED;
private int backageColor = Color.BLUE;

public MyTextView(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
this.setBackgroundColor(this.backageColor);
}

private int getHightSize(int measureSpec) {
int size = 0;
int spec_mode = MeasureSpec.getMode(measureSpec);
int spec_size = MeasureSpec.getSize(measureSpec);
if (spec_mode == MeasureSpec.EXACTLY) {
System.out.println("exactly");
size = spec_size;
} else if (spec_mode == MeasureSpec.AT_MOST) {
System.out.println("at_most");
size = textSize;
} else if (spec_mode == MeasureSpec.UNSPECIFIED) {
System.out.println("unspecified");
size = 100;
}
return size;
}

private int getWidthSize(int measureSpec) {
int size = 0;
int spec_mode = MeasureSpec.getMode(measureSpec);
int spec_size = MeasureSpec.getSize(measureSpec);
if (spec_mode == MeasureSpec.EXACTLY) {
System.out.println("exactly");
size = spec_size;
} else if (spec_mode == MeasureSpec.AT_MOST) {
System.out.println("at_most");
size = textSize * text.length();
} else if (spec_mode == MeasureSpec.UNSPECIFIED) {
System.out.println("unspecified");
size = 100;
}
return size;
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
this.setMeasuredDimension(this.getWidthSize(widthMeasureSpec), this.getHightSize(heightMeasureSpec));
}

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
Paint paint = new Paint();
paint.setTextSize(textSize);
paint.setColor(this.textColor);
System.out.println("核潜艇 =" + this.getMeasuredHeight());
Toast.makeText(this.context, "size" + this.getMeasuredHeight(),
Toast.LENGTH_LONG).show();
// 坐标是左下角
float left = this.getPaddingLeft();
float height = this.getMeasuredHeight();//就是textSize的值。
float bottom = height - this.getPaddingBottom() - height*15/100;
canvas.drawText(text, left, bottom, paint);
}
}

用自定义View设置字体变化颜色“<span style="color: rgb(0, 176, 80); font-family: 微软雅黑; font-size: 22px; line-height: 33px;">让文字的颜色每隔一秒种变化一次，即文字颜色为红色和黄色，每隔一秒变化一次，则把MyTextView类改为”</span>

<span style="color: rgb(0, 176, 80); font-family: 微软雅黑; font-size: 22px; line-height: 33px;"></span><pre name="code" class="java">public class MyTextView extends View {
private String text = "中华人民共和国";
private int textSize = 100;
private Context context;
private int textColor = Color.RED;
private int backageColor = Color.BLUE;

public MyTextView(Context context, AttributeSet attrs) {
super(context, attrs);
this.context = context;
this.setBackgroundColor(this.backageColor);
}

private int getHightSize(int measureSpec) {
int size = 0;
int spec_mode = MeasureSpec.getMode(measureSpec);
int spec_size = MeasureSpec.getSize(measureSpec);
if (spec_mode == MeasureSpec.EXACTLY) {
System.out.println("exactly");
size = spec_size;
} else if (spec_mode == MeasureSpec.AT_MOST) {
System.out.println("at_most");
size = textSize;
} else if (spec_mode == MeasureSpec.UNSPECIFIED) {
System.out.println("unspecified");
size = 100;
}
return size;
}

private int getWidthSize(int measureSpec) {
int size = 0;
int spec_mode = MeasureSpec.getMode(measureSpec);
int spec_size = MeasureSpec.getSize(measureSpec);
if (spec_mode == MeasureSpec.EXACTLY) {
System.out.println("exactly");
size = spec_size;
} else if (spec_mode == MeasureSpec.AT_MOST) {
System.out.println("at_most");
size = textSize * text.length();
} else if (spec_mode == MeasureSpec.UNSPECIFIED) {
System.out.println("unspecified");
size = 100;
}
return size;
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
this.setMeasuredDimension(this.getWidthSize(widthMeasureSpec),
this.getHightSize(heightMeasureSpec));
}

int i = 0;

@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
int textColor = 0;
i++;
if (i % 2 == 0) {
textColor = this.textColor;
}else {
textColor = Color.YELLOW;
}
Paint paint = new Paint();
paint.setTextSize(textSize);
paint.setColor(textColor);
System.out.println("核潜艇 =" + this.getMeasuredHeight());
Toast.makeText(this.context, "size" + this.getMeasuredHeight(),
Toast.LENGTH_LONG).show();
// 坐标是左下角
float left = this.getPaddingLeft();
float height = this.getMeasuredHeight();// 就是textSize的值。
float bottom = height - this.getPaddingBottom() - height * 15 / 100;
canvas.drawText(text, left, bottom, paint);

try {
Thread.sleep(1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
this.invalidate();
}
}

<span style="font-family: 微软雅黑; font-size: 22px; line-height: 33px;"></span><pre name="code" class="java" style="font-size: 22px; line-height: 33px;"><span style="color:#330033;">在封装类里面的set写invalidate()方法，能给自定义的View跳转传值</span><pre name="code" class="java">package xena.act;

import xena.view.MyView;
import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Color;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.LinearLayout;

public class MainActivity extends Activity implements OnClickListener {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
//		setContentView(R.layout.activity_main);
MyView myView = new MyView(this);
myView.setBackgroundColor(Color.YELLOW);
setContentView(myView);
myView.setR(40);
myView.setStr("中华人民共和国");

myView.setOnClickListener(this);
}
@Override
protected void onStart() {
super.onStart();
}
@Override
public void onClick(View v) {//v是事件源
MyView myView = (MyView) v;
myView.setStr("华清远见");
}
}
/*******************************************************

<pre name="code" class="java">package xena.view;

import xena.act.R;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.View;

public class MyView extends View {
private Context context;
private float r = 100;
private String str = "小";
private final String NS = "http://www.hqyj.com";// 名称空间
private boolean flag;

public float getR() {
return r;
}

public void setR(float r) {
this.r = r;
this.invalidate();//触发onDraw方法的执行
}

public String getStr() {
return str;
}

public void setStr(String str) {
this.str = str;
//	this.invalidate();//触发onDraw方法的执行View的监听事件
}

public boolean isFlag() {
return flag;
}

public void setFlag(boolean flag) {
this.flag = flag;
this.invalidate();//触发onDraw方法的执行
}

// 用于自定义View当作标签时用的
public MyView(Context context, AttributeSet attrs) {
super(context, attrs);

}

// 用于new MyView(...)用的
public MyView(Context context) {
super(context);
}

// 用于绘制界面上的内容,当界面显示时调用
@Override
protected void onDraw(Canvas canvas) {// canvas画布对象
super.onDraw(canvas);
// 创建笔 画
Paint paint = new Paint();
paint.setColor(Color.BLUE);
// 画圆
canvas.drawCircle(30, 30, this.r, paint);
paint.setColor(Color.RED);

if (flag) {
canvas.drawCircle(30, 30, 5, paint);
}
// 画字
// 参数1：被绘制的字符串, 参数2,3：指字符串每一个字符的左下角坐标
paint.setTextSize(30);// 设置文字大小
canvas.drawText(this.str, 30, 30, paint);
}
}