Android studio 项目常见问题_build task failed. open the run window to view det

1. 找不到类,JAR包导入失败

import android.support.v7.app.AppCompatActivity 报错

解决办法

//compile 'com.android.support:appcompat-v7:30.+'
    compile 'com.android.support:appcompat-v7:+'

2.Build task failed 构建任务失败

解决办法

settings/compile/command-line options -x app:mockable androidJar

3.安卓支持最小版本大于当前构建工具版本（gradle)

解决办法：

安装多个版本，再次安装新版本时候，uninstall prev version 去掉勾选

4.instant 任务失败

代码变更时，及时更新到模拟器失败，再settings/build/instant 去掉勾选

5.run:app:clean 任务失败

build 结果目录是svn目录，导致clean失败，再svn设置中去掉该马路，svn/ignore_recv_list

6.安装后，启动android-studio SDK找不到，

点击cancel,然后安装sdk

7.A WebView method was called on thread 'JavaBridge'. All WebView methods must be called on the same thread

webView.loadUrl(Const.SERVER_DOMAIN + url);
//换成下面的写法
webView.post(new Runnable() {
    @Override
    public void run() {
        webView.loadUrl(Const.SERVER_DOMAIN + url);
    }
});

8. alert 重写，使用TOAST后，只执行一次。

WebChromeClient client = new WebChromeClient(){
    @Override
    public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
        Log.e(TAG, "onJsAlert: " + message );
        Toast.makeText(WelcomeActivity.this, message, Toast.LENGTH_SHORT).show();
        //添加result.confirm()或者cancel();
        result.confirm();
        return true;
    }
};

9.android webview 页面跳转没有发生作用

解决办法：自定义javascriptinterface，调用webview.loadurl实现页面跳转

    @JavascriptInterface
    public void redirect(String url){
        webView.post(new Runnable() {
            @Override
            public void run() {
                webView.loadUrl(Const.SERVER_DOMAIN + url);
            }
        });
    }

10.安卓WebView页面跳转，自动使用浏览器打开

mWebView.setWebViewClient(new WebViewClient());

11.java.io.FileNotFoundException: /storage/emulated/0/a.apk: open failed: EACCES (Permission denied)

android 文件访问权限问题，

<application
        android:requestLegacyExternalStorage="true"

int REQUEST_EXTERNAL_STORAGE = 1;
        String[] PERMISSIONS_STORAGE = {
                Manifest.permission.READ_EXTERNAL_STORAGE,
                Manifest.permission.WRITE_EXTERNAL_STORAGE
        };
        int permission = ActivityCompat.checkSelfPermission(UpdateActivity.this, Manifest.permission.WRITE_EXTERNAL_STORAGE);
 
        if (permission != PackageManager.PERMISSION_GRANTED) {
            // We don't have permission so prompt the user
            ActivityCompat.requestPermissions(
                    UpdateActivity.this,
                    PERMISSIONS_STORAGE,
                    REQUEST_EXTERNAL_STORAGE
            );
        }

12.D/NetworkSecurityConfig: No Network Security Config specified, using platform default

访问HTTPS图片资源，不报错，也无法访问页面，

解决办法，换成HTTP图片资源即可