前言
当android系统的UI不能满足我们的设计或需求时，我们就需要自定义view来实现我们的目的，今天打算总结一下自定义view的几种常见方式。在此之前，学习了http://www.cnblogs.com/jiayongji/p/5560806.html 。受益良多，本文有参考其中的内容。
三种方式
自定义控件的实现有三种方式：组合控件、自绘控件和继承控件。下面将分别对这三种方式进行介绍。
组合控件
组合控件，即将本有的控件组合起来使用，形成新的控件。下面给大家介绍一种标题组合控件。
1、布局文件，可以在这个地方将控件组合起来使用，形成新的控件。
2、创建一个类CustomTitleView ，继承自RelativeLayout：
import android.content.Context;
import android.util.AttributeSet;
import android.view.View;
import android.widget.ImageView;
import android.widget.RelativeLayout;
import android.widget.TextView;
public class CustomTitleView extends RelativeLayout {
private ImageView back;
private TextView title;
private TextView rightText;
private TitleListener listener;
public CustomTitleView(Context context) {
this(context, null);
}
public CustomTitleView(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public CustomTitleView(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
View.inflate(context, R.layout.view_title, this);
initView();
setEvent();
}
public void setTitleData(String titleText) {
title.setText(titleText);
}
public void setListener(TitleListener listener) {
this.listener = listener;
}
private void initView() {
back = (ImageView) findViewById(R.id.back);
title = (TextView) findViewById(R.id.title_text);
rightText = (TextView) findViewById(R.id.right_text);
}
private void setEvent() {
back.setOnClickListener(v -> listener.onBack());
rightText.setOnClickListener(v -> listener.onRight());
}
public interface TitleListener {
void onBack();
void onRight();
}
}
3、以上，我们的组合控件View就已经完成，使用也很方便，如下:
title = (CustomTitleView) findViewById(R.id.title);
title.setTitleData("TEST");
title.setListener(new CustomTitleView.TitleListener() {
@Override
public void onBack() {
finish();
}
@Override
public void onRight() {
//no-op
}
});
4、运行效果如下：
组合控件
继承控件
继承控件就是，继承已有的控件，保留需要的功能，引入新的特性。这种自定义方法是最常见，使用最广泛的。比如说自定义Dialog等。
1、创建dialog的布局文件
2、创建CustomDialog类，继承自Dialog，并实现需要的一些接口。
public class LikeIosDialog extends Dialog {
public LikeIosDialog(Context context, int theme) {
super(context, theme);
}
public void onDismiss() {
if (isShowing()) {
dismiss();
}
}
public static class Builder {
private Button leftButton;
private Button rightButton;
private TextView dialogTitle;
private TextView dialogContent;
private View lineVertical;
private String message;
private String title;
private String leftButtonText;
private String rightButtonText;
private View.OnClickListener leftButtonClickListener;
private View.OnClickListener rightButtonClickListener;
private boolean isSingle = false;
private View layout;
private LikeIosDialog dialog;
public Builder(Context context) {
dialog = new LikeIosDialog(context, R.style.Dialog);
LayoutInflater inflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
layout = inflater.inflate(R.layout.layout_dialog, null);
dialog.addContentView(layout, new ViewGroup.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT));
dialog.setContentView(layout);
dialog.setCancelable(true);
dialog.setCanceledOnTouchOutside(false);
}
public LikeIosDialog createDialog() {
initView();
setText();
setEvent();
return dialog;
}
private void initView() {
leftButton = (Button) layout.findViewById(R.id.left_button);
rightButton = (Button) layout.findViewById(R.id.right_button);
dialogContent = (TextView) layout.findViewById(R.id.dialog_content);
dialogTitle = (TextView) layout.findViewById(R.id.dialog_title);
lineVertical = layout.findViewById(R.id.line_vertical);
}
private void setText() {
if (isSingle) {
leftButton.setVisibility(View.GONE);
lineVertical.setVisibility(View.GONE);
} else {
leftButton.setVisibility(View.VISIBLE);
lineVertical.setVisibility(View.VISIBLE);
}
dialogContent.setText(message);
leftButton.setText(leftButtonText);
rightButton.setText(rightButtonText);
dialogTitle.setText(title);
}
private void setEvent() {
leftButton.setOnClickListener(leftButtonClickListener);
rightButton.setOnClickListener(rightButtonClickListener);
}
public Builder setMessage(String message) {
this.message = message;
return this;
}
public Builder setTitle(String title) {
this.title = title;
return this;
}
public Builder setLeftButton(String leftButtonText, View.OnClickListener leftButtonClickListener) {
this.leftButtonText = leftButtonText;
this.leftButtonClickListener = leftButtonClickListener;
return this;
}
public Builder setRightButton(String rightButtonText, View.OnClickListener rightButtonClickListener) {
this.rightButtonText = rightButtonText;
this.rightButtonClickListener = rightButtonClickListener;
return this;
}
public Builder isSingleButton(boolean isSingleButton) {
this.isSingle = isSingleButton;
return this;
}
public Builder setSingleButton(String rightButtonText, View.OnClickListener rightButtonClickListener) {
this.rightButtonText = rightButtonText;
this.rightButtonClickListener = rightButtonClickListener;
return this;
}
}
@Override
public boolean onKeyDown(int keyCode, KeyEvent event) {
if (keyCode == KeyEvent.KEYCODE_BACK) {
dismiss();
}
return super.onKeyDown(keyCode, event);
}
}
3、使用
private BukkaDialog.Builder deleteDialogBuilder;
private BukkaDialog deleteDialog;
deleteDialogBuilder = new BukkaDialog.Builder(this);
deleteDialog = deleteDialogBuilder
.setTitle(getString(R.string.dialog_title))
.setMessage(getString(R.string.dialog_content))
.isSingleButton(false)
.setRightButton(getString(R.string.ok), v1 -> {
//TODO something
deleteDialog.onDismiss();
})
.setLeftButton(getString(R.string.cancel), v12 -> deleteDialog.onDismiss())
.createDialog();
deleteDialog.show();
4、运行效果如下：
继承控件
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。在自定义View中，难度最大，但是效果最好的一种方法，下面就实现一个简单圆圈的画法。
1、创建CounterView类，继承自View，同时可以实现OnClickListener等接口：
package com.monoqn.widgets;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.util.AttributeSet;
import android.view.Display;
import android.view.View;
import android.view.WindowManager;
public class CounterView extends View {
private Paint mPaint;
private Context mContext;
private int screenWidth;
private int screenHeight;
public CounterView(Context context) {
super(context, null);
init();
}
public CounterView(Context context, AttributeSet attrs) {
super(context, attrs);
mContext = context;
init();
}
private void init() {
mPaint = new Paint();
mPaint.setAntiAlias(true);
mPaint.setColor(Color.RED);
mPaint.setStyle(Paint.Style.STROKE);
mPaint.setStrokeWidth(20);
WindowManager wm = (WindowManager) mContext.getSystemService(Context.WINDOW_SERVICE);
Display display = wm.getDefaultDisplay();
screenWidth = display.getWidth();
screenHeight = display.getHeight();
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawCircle(screenWidth / 2, screenHeight / 2, 50, mPaint);
}
}
2、在activity_main.xml中引入该自定义布局：
3、运行效果如下：
自绘控件
小结
自定义view的内容到这里就结束了，相信对于简单的自定义view大家都可以简单的应对了。当然学习是无止境的，希望大家可以不断地探索学习，其中还有很多东西值得大家学习。下一期我想和大家分享的是：深度探索Activity！
原文链接:
[http://www.jianshu.com/p/61d338b30c4d)