自定义控件之-TopBar

迈不过友情╰ 2022-07-11 05:47 216阅读 0赞

一个项目中大部分的界面title一般都是风格相同的，本文介绍title的自定义模板。  
1.首先是attrs.xml中声明自定义控件的属性  
2.新建TopBar继承RelativeLayout，定义属性，和控件方法  
3.在布局文件中摆放自定义控件  
4.在代码中调用控件自定义方法  
先看下效果图：  
![这里写图片描述][SouthEast]

1.新建attrs.xml，目录：main/res/values/attrs.xml  
![这里写图片描述][SouthEast 1]

<?xml version="1.0" encoding="utf-8"?>
    <resources>
        <declare-styleable name="Topbar">
            <attr name="mTitle" format="string" />
            <attr name="mTitleTextSize" format="dimension" />
            <attr name="mTitleTextColor" format="color|reference" />
            <attr name="leftText" format="string" />
            <attr name="leftTextColor" format="color" />
            <attr name="leftBackground" format="color|reference" />
            <attr name="rightText" format="string" />
            <attr name="rightTextColor" format="color" />
            <attr name="rightBackground" format="color|reference" />
        </declare-styleable>
    
    </resources>

2.自定义控件TopBar。

package com.interjoy.democustom;
    
    import android.content.Context;
    import android.content.res.TypedArray;
    import android.graphics.drawable.Drawable;
    import android.util.AttributeSet;
    import android.view.Gravity;
    import android.view.View;
    import android.widget.Button;
    import android.widget.RelativeLayout;
    import android.widget.TextView;
    
    /** * Created by ylwang on 2017/1/17. */
    public class Topbar extends RelativeLayout { 
        private Button leftButton, rightButton;
        private TextView tvTitle;
    
        private int leftTextColor;
        private Drawable leftBackground;
        private String leftText;
        private LayoutParams leftParams;//定义宽高属性
    
        private int rightTextColor;
        private Drawable rightBackground;
        private String rightText;
        private LayoutParams rightParams;
    
        private float titleTextSize;
        private int titleTextColor;
        private String title;
        private LayoutParams titleParams;
    
        public Topbar(Context context) {
            super(context);
    
        }
    
        public Topbar(Context context, AttributeSet attrs) {
            super(context, attrs);
            //从xml中获取我们定义好的属性
            TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.Topbar);
            //TypedArray中是以键值对形式存储属性，键由AS按照规则命名的，“styleable名_属性名”
            leftTextColor = ta.getColor(R.styleable.Topbar_leftTextColor, 0);
            leftBackground = ta.getDrawable(R.styleable.Topbar_leftBackground);
            leftText = ta.getString(R.styleable.Topbar_leftText);
    
            rightTextColor = ta.getColor(R.styleable.Topbar_rightTextColor, 0);
            rightBackground = ta.getDrawable(R.styleable.Topbar_rightBackground);
            rightText = ta.getString(R.styleable.Topbar_rightText);
    
            title = ta.getString(R.styleable.Topbar_mTitle);
            titleTextSize = ta.getDimension(R.styleable.Topbar_mTitleTextSize, 0);
            titleTextColor = ta.getColor(R.styleable.Topbar_mTitleTextColor, 0);
    
            ta.recycle();//用完记得回收，避免内存浪费，或者缓存引起其他错误
    
            final int TAG_LEFT = 0x001;
            final int TAG_RIGHT = 0x002;
    
            //动态生成控件
            leftButton = new Button(context);
            rightButton = new Button(context);
            tvTitle = new TextView(context);
            //给控件设置属性
            leftButton.setBackground(leftBackground);
            leftButton.setText(leftText);
            leftButton.setTextColor(leftTextColor);
            leftButton.setTag(TAG_LEFT);//为了绑定监听时区分，设置一个tag
    
            rightButton.setBackground(rightBackground);
            rightButton.setText(rightText);
            rightButton.setTextColor(rightTextColor);
            rightButton.setTag(TAG_RIGHT);
    
            tvTitle.setText(title);
            tvTitle.setTextColor(titleTextColor);
            tvTitle.setTextSize(titleTextSize);
            tvTitle.setGravity(Gravity.CENTER);//设置居中
            //给Topbar设置背景颜色
            setBackgroundColor(0xFFF59563);
            //设置宽高及一些规则属性
            leftParams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
            leftParams.addRule(RelativeLayout.ALIGN_PARENT_LEFT, TRUE);//添加规则左对齐父控件，注意第二个参数TRUE全大写
            addView(leftButton, leftParams);//把控件添加到布局中
    
            rightParams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
            rightParams.addRule(RelativeLayout.ALIGN_PARENT_RIGHT, TRUE);
            addView(rightButton, rightParams);
    
            titleParams = new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);//高度填充父控件
            titleParams.addRule(RelativeLayout.CENTER_IN_PARENT, TRUE);
            addView(tvTitle, titleParams);
            //4.绑定监听，调接口方法
            OnClickListener sysListener = new OnClickListener() {
                @Override
                public void onClick(View v) {
                    switch ((int) v.getTag()) {
                        case TAG_LEFT:
                            listener.leftClick();
                            break;
                        case TAG_RIGHT:
                            listener.rightClick();
                            break;
                    }
                }
            };
            leftButton.setOnClickListener(sysListener);
            rightButton.setOnClickListener(sysListener);
        }
    
        //1.定义接口和抽象方法
        public interface TopbarClickListener { 
            //左侧点击
            void leftClick();
    
            //右侧点击
            void rightClick();
        }
    
        //2.声明接口对象
        private TopbarClickListener listener;
    
        //3.定义对外监听方法传参接口对象
        public void setTopbarClickListener(TopbarClickListener listener) {
            this.listener = listener;
        }
    
        //设置左侧button是否可见，同样可以设置右侧等，此处仅拿左侧button来示例
        public void setLeftVisinility(boolean flag) {
            if (flag) leftButton.setVisibility(VISIBLE);
            else leftButton.setVisibility(INVISIBLE);
        }
    
        public Topbar(Context context, AttributeSet attrs, int defStyleAttr) {
            super(context, attrs, defStyleAttr);
        }
    }

3.在activity\_main.xml布局文件中摆放自定义控件，注意自定义属性的调用，添加如图代码  
![这里写图片描述][SouthEast 2]

<?xml version="1.0" encoding="utf-8"?>
    <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:custom="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" tools:context="com.interjoy.democustom.MainActivity">
    
        <com.interjoy.democustom.Topbar android:id="@+id/topbar" android:layout_width="match_parent" android:layout_height="50dp" custom:leftBackground="#006666" custom:leftText="Back" custom:leftTextColor="#ffffff" custom:mTitle="自定义标题" custom:mTitleTextColor="#123412" custom:mTitleTextSize="10sp" custom:rightBackground="#006666" custom:rightText="More" custom:rightTextColor="#ffffff" />
    
    </RelativeLayout>

4.在代码中加载布局，调用自定义控件的方法

package com.interjoy.democustom;
    
    import android.os.Bundle;
    import android.support.v7.app.AppCompatActivity;
    import android.widget.ImageView;
    import android.widget.Toast;
    
    public class MainActivity extends AppCompatActivity { 
        private Topbar topbar;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            initView();
            setListener();
        }
    
        private <T> T f(int id) {
            return (T) findViewById(id);
        }
    
        private void initView() {
            topbar = f(R.id.topbar);
        }
    
        private void setListener() {
            topbar.setTopbarClickListener(new Topbar.TopbarClickListener() {
                @Override
                public void leftClick() {
                    Toast.makeText(MainActivity.this, "点击左侧", Toast.LENGTH_SHORT).show();
                }
    
                @Override
                public void rightClick() {
                    Toast.makeText(MainActivity.this, "点击More", Toast.LENGTH_SHORT).show();
                }
            });
        }
    
    
    }

总结下接口回调四个步骤：  
1.定义接口和抽象方法  
2.声明接口对象  
3.设置对外暴露的方法传参接口对象  
4.在系统原生监听中调用接口的抽象方法。

[SouthEast]: /images/20220711/de052118883947ff9520eb5a3d4f5b80.png
[SouthEast 1]: /images/20220711/f145b17e50d04fd3bd0ec9c16a8c1b7f.png
[SouthEast 2]: /images/20220711/0c71d8420ee147f5915f39d37c077937.png