App inventor:aix程式碼練習2

此為取得快照的aix原始檔，原始連結。

https://community.appinventor.mit.edu/t/f-os-simple-screenshot-extension/54125

以下僅加上註解 ，便於了解 ：

import android.app.Activity;

import android.content.Context;

import com.google.appinventor.components.annotations.*;

import com.google.appinventor.components.common.ComponentCategory;

import com.google.appinventor.components.runtime.AndroidNonvisibleComponent;

import com.google.appinventor.components.runtime.ComponentContainer;

import com.google.appinventor.components.runtime.EventDispatcher;

import com.google.appinventor.components.runtime.AndroidViewComponent;

import android.view.View;

import android.graphics.Bitmap;

import java.io.FileOutputStream;

import android.graphics.Bitmap.CompressFormat;

import android.content.pm.PackageManager;

import android.os.Environment;

import java.io.File;

import java.lang.Enum;

@DesignerComponent(

version = 2,

description = "A non-visible extension to take screenshots.",

category = ComponentCategory.EXTENSION,

nonVisible = true,

iconName = "https://docs.google.com/drawings/d/e/2PACX-1vQCI87PHLBF0jb8QWyYmIRQSjjNW3EFXf-qpsWCvBYkUQ9vEgPAB8SpxcMpblxNpbIYrjCjLrRLIU2c/pub?w=16&h=16")

//簡單物件

@SimpleObject(external = true)

//Libraries

//使用者庫

@UsesLibraries(libraries = "")

//Permissions

@UsesPermissions(permissionNames = "")

//Ta要你建立的package英文相同

public class Ta extends AndroidNonvisibleComponent {

//Activity and Context

private Context context;

private Activity activity;

//此class的主要建構式,在此將外在ui的元件和這個function的變數綁定，Ta要與類別名相同

public Ta(ComponentContainer container){

super(container.$form());

this.activity = container.$context();

this.context = container.$context();

}

//取得快照的主要程式碼

@SimpleFunction(description = "Takes a screenshot of the current app, with the given quality, compressFormat and saves the screenshot as the given path.")

public void TakeScreenshot(int quality, String compressFormat, String path) {

try {

//設定mPath為你設定的路徑

String mPath = path;

//預設壓縮成jpg

CompressFormat cp = CompressFormat.JPEG;

//假如compressFormat的值是png，就壓成png格式

if (compressFormat == "PNG") {

//假如compressFormat的值是png，就壓成WEBP格式

cp = CompressFormat.PNG;

} else if (compressFormat == "WEBP") {

cp = CompressFormat.WEBP;

}

//設定vi為activity.getWindow().getDecorView().getRootView(),反正就是取得視圖

View v1 = activity.getWindow().getDecorView().getRootView();

//在使用getDrawingCache前要先setDrawingCacheEnabled(true)

v1.setDrawingCacheEnabled(true);

//透過Bitmap.createBitmap這個方法將圖片顯示出來

Bitmap bitmap = Bitmap.createBitmap(v1.getDrawingCache());

//用完getDrawingCache，將setDrawingCacheEnabled設為false

v1.setDrawingCacheEnabled(false);

//設定檔案要儲存的路徑

File imageFile = new File(mPath);

//設定要儲存的路徑

FileOutputStream outputStream = new FileOutputStream(imageFile);

//將bitmap開始壓縮到某個位置存起來，參數1是壓縮的形式，參數2是品質，第三個是儲存的路徑

bitmap.compress(cp, quality, new FileOutputStream(path));

//執行SimpleEvent裡的EventDispatcher.dispatchEvent(this, "SavedScreenshot", path);

SavedScreenshot(imageFile.toString());

//釋放資源

outputStream.flush();

outputStream.close();

}

catch(Throwable e) {

//失敗了會去執行SimpleEvent裡的EventDispatcher.dispatchEvent(this, "Failed", error);

Failed(e.getMessage());

}

}

//設定屬性，回傳JPEG

@SimpleProperty(description = "A compress format block.")

public String Jpeg() {

return "JPEG";

}

//設定屬性，綠色積木，回傳PNG

@SimpleProperty(description = "A compress format block.")

public String Png() {

return "PNG";

}

//設定屬性，回傳Webp,WebP（發音：weppy）是一種同時提供了有損壓縮與無失真壓縮（可逆壓縮）的圖片檔案格式。

@SimpleProperty(description = "A compress format block. This block will only work for devices smaller than Android 10.")

public String Webp() {

return "WEBP";

}

//失敗事件反應。Failed

@SimpleEvent(description = "This event is fired when the extension has failed to take the screenshot.")

public void Failed (String error) {

EventDispatcher.dispatchEvent(this, "Failed", error);

}

//成功事件反應

@SimpleEvent(description = "This event is fired when the extension has taken the screenshot in the given path.")

public void SavedScreenshot (String path) {

EventDispatcher.dispatchEvent(this, "SavedScreenshot", path);

}

//Function反應

@SimpleFunction(description = "Returns whether the application has the write permission. This is mandatory if you use this extension.")

public boolean IsWritePermissionGranted() {

//android 9.0之後，要寫入資料夾，要先獲得寫入的權限才能寫入

String permission = android.Manifest.permission.WRITE_EXTERNAL_STORAGE;

int res = context.checkCallingOrSelfPermission(permission);

return (res == PackageManager.PERMISSION_GRANTED);

}

//此Function目的為取得檔案要儲存的資料夾

@SimpleFunction(description = "Returns an absolute path of the application specific directory of this app.")

public String ApplicationSpecificDirectory() {

String pkgName = context.getPackageName();

//回傳你要儲存檔案的路徑

return "/storage/emulated/0/Android/data/" + pkgName + "/files/";

}

}