Android自定义Toast视图和动画

在Android Toast基础与原理中，我们对Toast的源码进行了分析。我们也对Toast的实现原理有了一定的了解。接下来我们将编写一个工具类，来完成Toast的自定义视图和动画。

一、实现原理分析

通过上篇文章，我们知道Toast是通过内部类TN（一个ITransientNotification对象）进行实现。通过与INotificationManager进行管理。在源码中，我们在TN的构造函数中：

TN() {
// XXX This should be changed to use a Dialog, with a Theme.Toast
// defined that sets up the layout params appropriately.
final WindowManager.LayoutParams params = mParams;
params.height = WindowManager.LayoutParams.WRAP_CONTENT;
params.width = WindowManager.LayoutParams.WRAP_CONTENT;
params.format = PixelFormat.TRANSLUCENT;
params.windowAnimations = com.android.internal.R.style.Animation_Toast;
params.type = WindowManager.LayoutParams.TYPE_TOAST;
params.setTitle("Toast");
params.flags = WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
| WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
| WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE;
}

看到在params中设置Toast的显示动画。

params.windowAnimations = com.android.internal.R.style.Animation_Toast;

所以我们的实现思路就是通过反射获取到对应的WindowManager.LayoutParams对象，然后进行设置我们的动画即可。

二、工具类的实现

/**
* Created by Iflytek_dsw on 2017/7/4.
*/
public class ToastManager {

private Toast toast;
private Context context;
private static ToastManager instance;

private ToastManager(Context context){
this.context = context;
toast = new Toast(context);
}

/**
* 构造ToastManager对象
* @param context 上下文对象
* @return
*/
public static ToastManager getInstance(Context context) {
if(instance == null){
instance = new ToastManager(context);
}
return instance;
}

/**
* 自定义View和显示位置的Toast
* @param view  Toast的View视图
* @param gravity   Toast的显示位置
* @param xOffset   Toast在x方向上偏移量,x大于0往右，x小于0往左
* @param yOffset   Toast在y方向上偏移量,y值大于0往上，小于0往下
*/
public void makeToastSelfView(View view, int gravity,int xOffset, int yOffset){
if(toast == null){
toast = new Toast(context);
}

toast.setView(view);
toast.setGravity(gravity, xOffset, yOffset);
toast.setDuration(Toast.LENGTH_SHORT);
toast.show();
}

/**
* 构造带有动画的Toast
* @param tText 提示的文本
* @param animationID   style封装的动画资源id
*/
public void makeToastSelfAnimation(String tText,int animationID){
toast = Toast.makeText(context, tText, Toast.LENGTH_SHORT);
try {
Field mTNField = toast.getClass().getDeclaredField("mTN");
mTNField.setAccessible(true);
Object mTNObject = mTNField.get(toast);
Class tnClass = mTNObject.getClass();
Field paramsField = tnClass.getDeclaredField("mParams");
/**由于WindowManager.LayoutParams mParams的权限是private*/
paramsField.setAccessible(true);
WindowManager.LayoutParams layoutParams = (WindowManager.LayoutParams) paramsField.get(mTNObject);
layoutParams.windowAnimations = animationID;
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
toast.show();
}

/**
* 设置自定义View和Animation
* @param view  自定义View
* @param animationID   动画资源id
*/
public void makeToastSelfViewAnim(View view, int animationID){
if(toast == null){
toast = new Toast(context);
}

toast.setView(view);
try {
Field mTNField = toast.getClass().getDeclaredField("mTN");
mTNField.setAccessible(true);
Object mTNObject = mTNField.get(toast);
Class tnClass = mTNObject.getClass();
Field paramsField = tnClass.getDeclaredField("mParams");
/**由于WindowManager.LayoutParams mParams的权限是private*/
paramsField.setAccessible(true);
WindowManager.LayoutParams layoutParams = (WindowManager.LayoutParams) paramsField.get(mTNObject);
layoutParams.windowAnimations = animationID;
} catch (NoSuchFieldException e) {
e.printStackTrace();
} catch (IllegalAccessException e) {
e.printStackTrace();
}
toast.show();
}
}

三、体验Sample

1、自定义Toast的layout布局

首先我们自定义一个Toast的视图layout布局。

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal" android:layout_width="wrap_content"
android:gravity="center_vertical"
android:background="#000000"
android:padding="10dp"
android:layout_height="wrap_content">
<ImageView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@mipmap/dicus"/>
<TextView
android:id="@+id/tv_title"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="10dp"
android:text="发表评论+10松果"
android:textColor="#FFFFFF"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginLeft="20dp"
android:text="查看"
android:textColor="#E8C84A"/>
</LinearLayout>

2、自定义实现动画

1、新建anim文件夹，用于存储我们的enter和out动画。

enter

<?xml version="1.0" encoding="utf-8"?>
<scale xmlns:android="http://schemas.android.com/apk/res/android"
android:fromXScale="0"
android:toXScale="1"
android:pivotX="50%"
android:pivotY="50%"
android:fromYScale="1"
android:toYScale="1"
android:duration="1000">
</scale>

out

<?xml version="1.0" encoding="utf-8"?>
<set xmlns:android="http://schemas.android.com/apk/res/android">
<scale
android:fromXScale="1"
android:toXScale="0"
android:pivotX="50%"
android:pivotY="50%"
android:fromYScale="1"
android:toYScale="1"
android:duration="1000"
/>
</set>

style样式

<style name="MyToast" parent="Base.Animation.AppCompat.Dialog">
<item name="android:windowEnterAnimation">@anim/enter</item>
<item name="android:windowExitAnimation">@anim/out</item>
</style>

3、调用工具类实现

public class MainActivity extends AppCompatActivity {
private Button btn_toast;
private View toastView;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
LayoutInflater inflater = LayoutInflater.from(MainActivity.this);
toastView = inflater.inflate(R.layout.toastlayout, null);
btn_toast = (Button) findViewById(R.id.btn_toast);
btn_toast.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
ToastManager.getInstance(getApplicationContext()).
makeToastSelfViewAnim(toastView,R.style.MyToast);
}
});
}
}

效果图：