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一，前期基础知识储备

1）svg图片较大，所以需要压缩为zip包后放在服务器上，下载使用；

2）使用OKGO库进行网络资源下载；

3）使用工具库Blankj中的解压缩工具进行解压缩后，然后保存在本地；

4）下载并且解压缩zip成功后，删除本地zip包，只保留解压缩得到的svg资源。

二，上代码，具体实现

1）引入OKGO和Blankj依赖：

implementation 'com.lzy.net:okgo:3.0.4'implementation 'com.blankj:utilcode:1.25.9'

注：如果有使用RxJava的依赖，OKGO的依赖需要进行修改；另外此库已经停止维护。

2）使用OKGO前需要进行的声明：

        OkHttpClient.Builder builder = new OkHttpClient.Builder();        //全局的读取超时时间        builder.readTimeout(30000L, TimeUnit.MILLISECONDS);        //全局的写入超时时间        builder.writeTimeout(30000L, TimeUnit.MILLISECONDS);        //全局的连接超时时间        builder.connectTimeout(100000L, TimeUnit.MILLISECONDS);        builder.proxy(Proxy.NO_PROXY);        builder.hostnameVerifier(new HostnameVerifier() {            @Override            public boolean verify(String hostname, SSLSession session) {                try {                    if (TextUtils.isEmpty(hostname) || TextUtils.isEmpty(session.getPeerHost())) {                        return false;                    }                    return hostname.equals(session.getPeerHost());                } catch (Exception e) {                    return false;                }            }        });        OkGo.getInstance().init(this).setOkHttpClient(builder.build()).setRetryCount(3);

库已停止维护，所以后续随着targetSdkVersion的升级，声明也需要自己做出相应修改。博主应用版本为29。

3）下载zip包的代码实现：

   private void onDownLoadAndSaveSvg(String svgUrl, String svgName) {        if (NetCheckUtils.isNetWorkEnable(this)) {            /*Api29 Android10 存储结构有变 需要进行其他处理*/            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.Q) {                OkGo.<File>get(svgUrl)                        .execute(new FileCallback(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath()                                + File.separator + "lovedrawing", svgName + ".zip") {                            @Override                            public void onSuccess(Response<File> response) {                                Log.d(TAG, "onSuccess: file 下载成功");                                isDownLoad = true;                                String zipFileName = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath()                                        + File.separator + "lovedrawing" + File.separator + svgName + ".zip";                                svgUnzipPath = ZipAndReadSvgUtils.unZipDownlaodSvgToSdCard(PaintActivity.this,                                        zipFileName, svgName);                                File f = response.body();                                if (f != null && f.exists()) {                                    f.delete();                                }                                InputStream mInputStream = ZipAndReadSvgUtils.readSvgFromSdCard(PaintActivity.this, svgName);                                if (mInputStream != null) {                                    parseSvgXml(mInputStream);                                    drawingBoardView.init(PaintActivity.this, mInputStream);                                    initColorRecyData();                                    initPopuWindowLayout();                                } else {                                }                                noNetWorkRl.setVisibility(View.GONE);                            }                            @Override                            public void onError(Response<File> response) {                                Log.d(TAG, "onError: file出错,," + response + ",," + response.body()                                        + ",," + response.message() + ",," + response.getException() + ",," + response.isSuccessful());                                noNetWorkRl.setVisibility(View.VISIBLE);                            }                            @Override                            public void downloadProgress(Progress progress) {                                Log.d(TAG, "downloadProgress: 下载过程,," + progress.totalSize + ",," + progress);                            }                        });            } else {                onMIUIDownLoadAndSaveSvg(svgUrl, svgName);            }        } else {            noNetWorkRl.setVisibility(View.VISIBLE);            ToastUtil.showToast(PaintActivity.this, R.string.net_fail);        }    }

因为API29 的存储结构发生变化，所以需要单独再做一次下载处理，代码如下：

    private void onMIUIDownLoadAndSaveSvg(String svgUrl, String svgName) {        File tempFile = getExternalFilesDir("TempProject");        OkGo.<File>get(svgUrl)                .execute(new FileCallback((tempFile != null ? tempFile.getAbsolutePath() : null)                        + File.separator + "lovedrawing", svgName + ".zip") {                    @Override                    public void onSuccess(Response<File> response) {                        Log.d(TAG, "onSuccess: MIUI file 下载成功");                        isDownLoad = true;                        String zipFileName = null;                        if (tempFile != null) {                            zipFileName = tempFile.getAbsolutePath()                                    + File.separator + "lovedrawing" + File.separator + svgName + ".zip";                        }                        svgUnzipPath = ZipAndReadSvgUtils.unZipDownlaodSvgToSdCard(PaintActivity.this,                                zipFileName, svgName);                        File f = response.body();                        if (f != null && f.exists()) {                            f.delete();                        }                        InputStream mInputStream = ZipAndReadSvgUtils.readSvgFromSdCard(PaintActivity.this, svgName);                        if (mInputStream != null) {                            parseSvgXml(mInputStream);                            drawingBoardView.init(PaintActivity.this, mInputStream);                            initColorRecyData();                            initPopuWindowLayout();                        } else {                        }                        noNetWorkRl.setVisibility(View.GONE);                    }                    @Override                    public void onError(Response<File> response) {                        Log.d(TAG, "onError: MIUI file出错,," + response + ",," + response.body()                                + ",," + response.message() + ",," + response.getException() + ",," + response.isSuccessful());                        noNetWorkRl.setVisibility(View.VISIBLE);                    }                    @Override                    public void downloadProgress(Progress progress) {                        Log.d(TAG, "downloadProgress: MIUI 下载过程,," + progress.totalSize + ",," + progress);                    }                });    }

内部代码解析：

①svgUrl —— 即为放置svg zip包的网络服务器地址；

②下载成功后，将得到的zip包保存在本地的地址如下：

new FileCallback(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath()+ File.separator + "lovedrawing", svgName + ".zip")

③得到zip包，利用工具类进行解压缩，然后将下载好的zip进行删除：

String zipFileName = Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_DOWNLOADS).getAbsolutePath()                                        + File.separator + "lovedrawing" + File.separator + svgName + ".zip";                                svgUnzipPath = ZipAndReadSvgUtils.unZipDownlaodSvgToSdCard(PaintActivity.this,                                        zipFileName, svgName);                                File f = response.body();                                if (f != null && f.exists()) {                                    f.delete();                                }

4）使用到的ZipAndReadSvgUtils 解压缩工具类如下：

public class ZipAndReadSvgUtils {    private static final String TAG = "ZipAndReadSvgUtils";    private static final String SVGFILENAME = "_localSvg";    /**     * 正式项目中使用——解压缩网络下好的SVG     * @param context     * @param zipFileName     * @param svgName     */    public static String unZipDownlaodSvgToSdCard(Context context, String zipFileName,                                                  String svgName) {        String svgUnzipPath = "";        File zipFile = new File(zipFileName);        Log.d(TAG, "unZipDownlaodSvgToSdCard: 压缩文件所在地址," + zipFile.getAbsolutePath());        String fileName = "";        File saveJsonFile = context.getExternalFilesDir("netToLocalSvg");        if (saveJsonFile != null) {            fileName = saveJsonFile.getAbsolutePath() + File.separator + svgName + SVGFILENAME;        }        File file = new File(fileName);        try {            ZipUtils.unzipFile(zipFile, file);            List<File> files = FileUtils.listFilesInDir(file);            svgUnzipPath = files.get(0).getAbsolutePath();            Log.d(TAG, "unZipDownlaodSvgToSdCard: SVG解压缩文件地址，" + files.get(0).getAbsolutePath());        } catch (IOException e) {            e.printStackTrace();        }        return svgUnzipPath;    }    /**     * 正式项目中使用——读取存在本地SDCard下的SVG     * @param context     * @return     */    public static InputStream readSvgFromSdCard(Context context, String svgName) {        String fileName = "";        File saveJsonFile = context.getExternalFilesDir("netToLocalSvg");        if (saveJsonFile != null) {            fileName = saveJsonFile.getAbsolutePath() + File.separator + svgName + SVGFILENAME;        }        File file = new File(fileName);        InputStream is = null;        try {            List<File> files= FileUtils.listFilesInDir(file);            Log.d(TAG, "readSvgFromSdCard: 读，" + files.get(0));            String svgString = FileIOUtils.readFile2String(files.get(0));            is = ConvertUtils.string2InputStream(svgString, "UTF-8");            Log.d(TAG, "readSvgFromSdCard: 读取本地存储svg流为，" + is);        } catch (Exception e) {            e.printStackTrace();        }        return is;    }}

最终得到svg资源地址：

/storage/emulated/0/Android/data/com.love.drawing.draw/files/netToLocalSvg/animal_010_localSvg/animal_010.svg

三，知识延伸

自定义View中动态添加 父容器布局 —— 采用静态布局的形式添加

下面代码中的自定义View继承自帧布局 FrameLayout 。

        FrameLayout.LayoutParams lp = new LayoutParams(                ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT, Gravity.TOP | Gravity.END);        lp.setMargins(0, ConvertUtils.dp2px(64), width + ConvertUtils.dp2px(6), 0);        LayoutInflater inflater3 = LayoutInflater.from(mContext);        preControlLl = inflater3.inflate(R.layout.view_preview_ll, null);        LinearLayout closeRoot = preControlLl.findViewById(R.id.close_root);        TextView closeText = preControlLl.findViewById(R.id.close_text);        closeText.setTypeface(Typeface.createFromAsset(mContext.getAssets(), "fonts/Roboto-Regular.ttf"));        ImageView closeImg = preControlLl.findViewById(R.id.close_img);        closeRoot.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                ... ...            }        });        preControlLl.setLayoutParams(lp);        addView(preControlLl);

注：使用 LayoutParams 动态指定父容器的大小，位置，边距等信息。

静态布局 view_preview_ll 如下：

<?xml version="1.0" encoding="utf-8"?><com.game.jianbihua.view.RadiusCardView xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:app="http://schemas.android.com/apk/res-auto"    android:layout_width="wrap_content"    android:layout_height="25dp"    app:cardMaxElevation="4dp"    app:rcv_bottomLeftRadiu="3dp"    app:rcv_topLeftRadiu="3dp">    <LinearLayout        android:id="@+id/close_root"        android:layout_width="wrap_content"        android:layout_height="25dp"        android:layout_gravity="top|end"        android:background="@color/home_coins"        android:gravity="center"        android:orientation="horizontal">        <ImageView            android:id="@+id/close_img"            android:layout_width="6dp"            android:layout_height="12dp"            android:layout_gravity="center_vertical"            android:layout_marginStart="4dp"            android:scaleType="fitCenter"            android:src="@drawable/view_pre_left" />        <TextView            android:id="@+id/close_text"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_gravity="center_vertical"            android:layout_marginStart="4dp"            android:layout_marginEnd="4dp"            android:gravity="center"            android:text="Preview"            android:textColor="@color/pureWhite"            android:textSize="12sp" />    </LinearLayout></com.game.jianbihua.view.RadiusCardView>