android 自己写类似toast的消息提示安卓开发toast

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mob64ca1402a190 2024-02-23 17:53:25

文章标签 安卓开发自定义Toast android ide 自定义 文章分类 Android 移动开发

背景

吐司提示很常见，但系统的吐司有一个缺点，就是显示时长不能自定义，而自定义Toast可以实现这一点

实现步骤

整体思路是：活动窗口发出弹出吐司请求，然后中间层接收请求，发给调度层，调度层显示吐司

这里请求的传递就是方法的调用，显示和消除吐司的关键是调用windowManager的addView()和removeView()方法

下面，是具体的实现步骤

中间层MyToast

此类用来和活动窗口和调度层交互，代码如下

package com.example.songzeceng.client;

import android.content.Context;

public class MyToast {
    private static final int DEFAULT_DURATION = 1000;

    public static void showToast(Context context, int resId, int duration) {
        String str = context.getApplicationContext().getString(resId);
        showToast(context, str, duration);
    }

    public static void showToast(Context context, String string, int duration) {
        ToastManager manager = ToastManager.makeText(context.getApplicationContext(), string, duration);
        manager.show();
    }

    public static void showToast(Context context, String string) {
        showToast(context, string, DEFAULT_DURATION);
    }

    public static void showToast(Context context, int resId) {
        showToast(context, resId, DEFAULT_DURATION);
    }
}

通过传入duration来实现显示时长自主可控，而ToastManager就是调度层，它的makeText()方法初始化吐司view，并实例化自己，而后show()方法显示吐司。

调度层ToastManager

按照从初始化到显示的步骤来实现

初始化

public static ToastManager makeText(Context context, String text, int duration) {
        ToastManager toastManager = new ToastManager();
        toastManager.text = text;
        toastManager.context = context.getApplicationContext();
        View contentView = LayoutInflater.from(toastManager.context).inflate(R.layout.toast_layout, null);
        contentView.findViewById(R.id.toast_image).setVisibility(View.GONE);
        toastManager.duration = duration;
        toastManager.contentView = contentView;

        return toastManager;
    }

加载吐司的布局，其中把图标默认设置为不可见。

显示

public void show() {
        if (contentView == null || text == null || text.isEmpty()) {
            return;
        }
        TextView textView = contentView.findViewById(R.id.toast_text);
        textView.setText(text);
        ImageView imageView = contentView.findViewById(R.id.toast_image);
        imageView.setImageDrawable(drawable);
        imageView.setVisibility(drawable == null ? View.GONE : View.VISIBLE);

        handler.sendEmptyMessage(MSG_SHOW);
    }

设置text和drawable后，调用handler的发送空消息。

这个handler是我自定义的WeakHandler对象，目的是为了防止内存泄漏。其源代码如下

package com.example.songzeceng.client;

import android.os.Handler;
import android.os.Message;

import java.lang.ref.WeakReference;

public class WeakHandler extends Handler {
    private WeakReference<IHandler> handlerWeakReference;

    public WeakHandler(IHandler handler) {
        handlerWeakReference = new WeakReference<>(handler);
    }

    @Override
    public void handleMessage(Message msg) {
        if (handlerWeakReference == null || handlerWeakReference.get() == null) {
            return;
        }
        handlerWeakReference.get().handleMessage(msg);
    }
}

持有一个IHandler接口的弱引用(这样就不存在内存泄漏了)，这个IHandler接口对象就是要处理消息的对象，可以是Activity、Fragment等等。如果一个类要处理消息，只需要让自己实现IHandler接口，然后实例化一个WeakHandler对象，在构造方法里传入自己就行。

IHandler接口代码如下

package com.example.songzeceng.client;

import android.os.Message;

public interface IHandler {
    void handleMessage(Message message);
}

而后在ToastManager里只需如此

package com.example.songzeceng.client;

public class ToastManager implements IHandler {

    private WeakHandler handler = new WeakHandler(this);


    @Override
    public void handleMessage(Message message) {
       ....
    }
}

回到显示toast的show()方法，方法说明，一切的调度具体内容都是在handleMessage()里执行的，这个方法的代码如下所示

@Override
    public void handleMessage(Message message) {
        switch(message.what){
            case MSG_SHOW:
                if (layoutParams == null) {
                    WindowManager.LayoutParams params = new WindowManager.LayoutParams();
                    params.height = WindowManager.LayoutParams.WRAP_CONTENT;
                    params.width = WindowManager.LayoutParams.WRAP_CONTENT;
                    params.format = PixelFormat.TRANSLUCENT; // 设置半透明
                    params.windowAnimations = android.R.style.Animation_Toast; // view动画是吐司形式
                    params.type = WindowManager.LayoutParams.TYPE_TOAST; // view的类型是吐司
                    params.flags = WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                            | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                            | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE; // view在的时候，保持屏幕亮着，view不可触摸，不可获得焦点
                    params.setTitle("Toast");

                    if (gravity == Gravity.NO_GRAVITY) {
                        params.gravity = Gravity.BOTTOM | Gravity.CENTER_HORIZONTAL;
                        params.y = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 80,
                                contentView.getContext().getResources().getDisplayMetrics());
                        // 设置view重心和纵向位置
                    } else {
                        params.gravity = gravity;
                    }

                    layoutParams = params;
                }

                windowManager = (WindowManager) contentView.getContext().getSystemService(Context.WINDOW_SERVICE);
                // 获取windowManager
                if (windowManager != null) {
                    windowManager.addView(contentView, layoutParams);
                    // 给window添加view，显示之
                }

                if (duration > 0) {
                    handler.sendEmptyMessageDelayed(MSG_HIDE, duration);
                    // 显示一段时间后让view消失
                }
                break;
            case MSG_HIDE:
                if (contentView != null) {
                    windowManager.removeView(contentView);
                    // 移除view，view就消失了
                }
                break;
        }
    }

注释写的很明白，代码也都是程序化的代码，毋须赘述

最后贴一下ToastManager的完整代码

package com.example.songzeceng.client;

import android.content.Context;
import android.graphics.PixelFormat;
import android.graphics.drawable.Drawable;
import android.os.Message;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.WindowManager;
import android.widget.ImageView;
import android.widget.TextView;

public class ToastManager implements IHandler {
    public static final int MSG_SHOW = 0;
    public static final int MSG_HIDE = 1;

    private WeakHandler handler = new WeakHandler(this);
    private String text;
    private View contentView;
    private Drawable drawable;
    private int duration;
    private WindowManager windowManager;
    private WindowManager.LayoutParams layoutParams;
    private int gravity;
    private Context context;

    public static ToastManager makeText(Context context, String text, int duration) {
        ToastManager toastManager = new ToastManager();
        toastManager.text = text;
        toastManager.context = context.getApplicationContext();
        View contentView = LayoutInflater.from(toastManager.context).inflate(R.layout.toast_layout, null);
        contentView.findViewById(R.id.toast_image).setVisibility(View.GONE);
        toastManager.duration = duration;
        toastManager.contentView = contentView;

        return toastManager;
    }

    public void show() {
        if (contentView == null || text == null || text.isEmpty()) {
            return;
        }
        TextView textView = contentView.findViewById(R.id.toast_text);
        textView.setText(text);
        ImageView imageView = contentView.findViewById(R.id.toast_image);
        imageView.setImageDrawable(drawable);
        imageView.setVisibility(drawable == null ? View.GONE : View.VISIBLE);

        handler.sendEmptyMessage(MSG_SHOW);
    }

    public void setIcon(int resId) {
        if (context == null) {
            return;
        }
        drawable = context.getDrawable(resId);
    }

    public void cancel() {
        handler.removeMessages(MSG_SHOW);
        handler.removeMessages(MSG_HIDE);
        if (windowManager != null && contentView != null) {
            windowManager.removeView(contentView);
        }
    }

    @Override
    public void handleMessage(Message message) {
        switch(message.what){
            case MSG_SHOW:
                if (layoutParams == null) {
                    WindowManager.LayoutParams params = new WindowManager.LayoutParams();
                    params.height = WindowManager.LayoutParams.WRAP_CONTENT;
                    params.width = WindowManager.LayoutParams.WRAP_CONTENT;
                    params.format = PixelFormat.TRANSLUCENT; // 设置半透明
                    params.windowAnimations = android.R.style.Animation_Toast; // view动画是吐司形式
                    params.type = WindowManager.LayoutParams.TYPE_TOAST; // view的类型是吐司
                    params.flags = WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
                            | WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                            | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE; // view在的时候，保持屏幕亮着，view不可触摸，不可获得焦点
                    params.setTitle("Toast");

                    if (gravity == Gravity.NO_GRAVITY) {
                        params.gravity = Gravity.BOTTOM | Gravity.CENTER_HORIZONTAL;
                        params.y = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, 80,
                                contentView.getContext().getResources().getDisplayMetrics());
                        // 设置view重心和纵向位置
                    } else {
                        params.gravity = gravity;
                    }

                    layoutParams = params;
                }

                windowManager = (WindowManager) contentView.getContext().getSystemService(Context.WINDOW_SERVICE);
                // 获取windowManager
                if (windowManager != null) {
                    windowManager.addView(contentView, layoutParams);
                    // 给window添加view，显示之
                }

                if (duration > 0) {
                    handler.sendEmptyMessageDelayed(MSG_HIDE, duration);
                    // 显示一段时间后让view消失
                }
                break;
            case MSG_HIDE:
                if (contentView != null) {
                    windowManager.removeView(contentView);
                    // 移除view，view就消失了
                }
                break;
        }
    }
}

吐司布局

吐司布局就是一个横向的线性布局，左边图标，右边文字

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:padding="20dp"
    android:background="@drawable/toast_background"
    android:orientation="horizontal">

    <ImageView
        android:id="@+id/toast_image"
        android:layout_width="wrap_content"
        android:layout_height="match_parent" />

    <TextView
        android:id="@+id/toast_text"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_marginLeft="10dp" />

</LinearLayout>

吐司的背景是用xml写的drawable，放在drawable目录里，定义了背景颜色和圆角半径

<?xml version="1.0" encoding="utf-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android">
    <solid android:color="#24F4AB"/>
    <corners android:radius="5dp"/>
</shape>

活动窗口调用

调用代码如下：

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

        MyToast.showToast(getApplicationContext(), " 动画结束", 2 * 1000);
    }