長期補充,我隻是大自然的搬運工
1.擷取手機的寬度和高度
WindowManager wm = this.getWindowManager();
int width = wm.getDefaultDisplay().getWidth();
int height = wm.getDefaultDisplay().getHeight();
2.popupWindow布局居中顯示
popup.setHeight(LayoutParams.WRAP_CONTENT);
popup.setWidth(width*3/4); //為手機的寬度(上面的width)
popup.showAtLocation(listView, Gravity.CENTER,0,0);//s
3.判斷手機是否安裝某第三方app
項目中遇到,需要判斷支付寶是否安裝,彈出提示。像判斷微信是否安裝,自己的jar包中會有isWXAppInstalled的方法。但是支付寶貌似沒找到
想要判斷是否安裝第三方app,就必須知道包名,包名的話,隻能去反編譯了。從AndroidManifest 去找到對應的package屬性。
開發中,如果突然想改項目的包名,在Android Tools 中 rename Application Package就可以了
好了,言歸正傳,有了包名,隻要周遊這個手機中所有的應用的包名就可以了,網上找了一個可用的方法,我覺得寫的還是挺詳細的
/**
* 檢查手機上是否安裝了指定的軟體
* @param context
* @param packageName:應用包名 如 com.example.test
* @return
*/
private boolean isAvilible(Context context, String packageName){
//擷取packagemanager
final PackageManager packageManager = context.getPackageManager();
//擷取所有已安裝程式的包資訊
List<PackageInfo> packageInfos = packageManager.getInstalledPackages(0);
//用于存儲所有已安裝程式的包名
List<String> packageNames = new ArrayList<String>();
//從pinfo中将包名字逐一取出,壓入pName list中
if(packageInfos != null){
for(int i = 0; i < packageInfos.size(); i++){
String packName = packageInfos.get(i).packageName;
packageNames.add(packName);
}
}
//判斷packageNames中是否有目标程式的包名,有TRUE,沒有FALSE
return packageNames.contains(packageName);
}
4.關于拍照的回調傳回的資料的問題
在onActivityResult中,從傳回的Intent中,獲得的Uri uri = data.getData();uri在4.3—->4.4系統的時候産生了不同在4.4一下,可以直接使用,但是在4.4以後,傳回的是content://。。。。,會出現無法加載此圖檔。
private void handleData(Intent data) {
Uri uri = data.getData();
// 4.4以後新特征
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.KITKAT) {
String url = getPath(PersonalDataActivity.this, uri);
uri = Uri.fromFile(new File(url));
handleData(uri);
} else {
// 4.4以下
handleData(uri);
}
}
通過判斷當然系統的版本進行不同的處理,主要是getPath這個方法。網上也有這個方法,測試可用
// 4.4新特征
public String getPath(final Context context, final Uri uri) {
final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
// DocumentProvider
if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
// ExternalStorageProvider
if (isExternalStorageDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
if ("primary".equalsIgnoreCase(type)) {
return Environment.getExternalStorageDirectory() + "/"
+ split[1];
}
// TODO handle non-primary volumes
}
// DownloadsProvider
else if (isDownloadsDocument(uri)) {
final String id = DocumentsContract.getDocumentId(uri);
final Uri contentUri = ContentUris.withAppendedId(
Uri.parse("content://downloads/public_downloads"),
Long.valueOf(id));
return getDataColumn(context, contentUri, null, null);
}
// MediaProvider
else if (isMediaDocument(uri)) {
final String docId = DocumentsContract.getDocumentId(uri);
final String[] split = docId.split(":");
final String type = split[0];
Uri contentUri = null;
if ("image".equals(type)) {
contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;
} else if ("video".equals(type)) {
contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;
} else if ("audio".equals(type)) {
contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;
}
final String selection = "_id=?";
final String[] selectionArgs = new String[] { split[1] };
return getDataColumn(context, contentUri, selection,
selectionArgs);
}
}
// MediaStore (and general)
else if ("content".equalsIgnoreCase(uri.getScheme())) {
// Return the remote address
if (isGooglePhotosUri(uri))
return uri.getLastPathSegment();
return getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
/**
* Get the value of the data column for this Uri. This is useful for
* MediaStore Uris, and other file-based ContentProviders.
*
* @param context
* The context.
* @param uri
* The Uri to query.
* @param selection
* (Optional) Filter used in the query.
* @param selectionArgs
* (Optional) Selection arguments used in the query.
* @return The value of the _data column, which is typically a file path.
*/
public static String getDataColumn(Context context, Uri uri,
String selection, String[] selectionArgs) {
Cursor cursor = null;
final String column = "_data";
final String[] projection = { column };
try {
cursor = context.getContentResolver().query(uri, projection,
selection, selectionArgs, null);
if (cursor != null && cursor.moveToFirst()) {
final int index = cursor.getColumnIndexOrThrow(column);
return cursor.getString(index);
}
} finally {
if (cursor != null)
cursor.close();
}
return null;
}
/**
* @param uri
* The Uri to check.
* @return Whether the Uri authority is ExternalStorageProvider.
*/
public static boolean isExternalStorageDocument(Uri uri) {
return "com.android.externalstorage.documents".equals(uri
.getAuthority());
}
/**
* @param uri
* The Uri to check.
* @return Whether the Uri authority is DownloadsProvider.
*/
public static boolean isDownloadsDocument(Uri uri) {
return "com.android.providers.downloads.documents".equals(uri
.getAuthority());
}
/**
* @param uri
* The Uri to check.
* @return Whether the Uri authority is MediaProvider.
*/
public static boolean isMediaDocument(Uri uri) {
return "com.android.providers.media.documents".equals(uri
.getAuthority());
}
/**
* @param uri
* The Uri to check.
* @return Whether the Uri authority is Google Photos.
*/
public static boolean isGooglePhotosUri(Uri uri) {
return "com.google.android.apps.photos.content".equals(uri
.getAuthority());
}
開發的時候需要把自己開發時候的包改為4.4.因為DocumentsContract 是在4.4包中獨有的類。
4.3的開發包是找不到這個類的,會報紅。
5.把網絡圖檔轉化為存在本地
先将流轉化為bitmap對象
map = BitmapFactory.decodeStream(inStream);
然後再講bitmap存在本地。
BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));
map .compress(Bitmap.CompressFormat.JPEG, 80, bos);
其中的file可以調用這個File(String dirPath, String name) ,目錄加名字來構造
6.本地儲存圖檔之後需要重新整理相冊
//相冊掃描圖檔
Intent intent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
Uri uri = Uri.fromFile(new File(mFilePath));
intent.setData(uri);
sendBroadcast(intent);
7.需要判斷第三方應用是否安裝(代碼在上)
如果未安裝,跳轉下載下傳,調到浏覽器下載下傳
Intent intent = new Intent(Intent.ACTION_VIEW, Uri.parse("下載下傳網址"));
mContext.startActivity(intent);
如果安裝了,直接打開app
PackageManager packageManager = mContext.getPackageManager();
Intent intent1 = packageManager.getLaunchIntentForPackage("包名");
mContext.startActivity(intent1);
8.撥打電話
Intent intent = new Intent(Intent.ACTION_CALL, Uri.parse("tel:"+ "電話号碼"));
startActivity(intent);
9.跳轉到打電話的頁面
Intent intent = new Intent(Intent.ACTION_DIAL);
intent.setData(Uri.parse("tel:" + telephone));
context.startActivity(intent);
10.複制到剪切闆
public static void copy2Clipboard(Context context,String msg){
ClipboardManager cm = (ClipboardManager) context.getSystemService(Context.CLIPBOARD_SERVICE);
// 将文本内容放到系統剪貼闆裡。
ClipData clip = ClipData.newPlainText("simple text", msg);
// Set the clipboard's primary clip.
cm.setPrimaryClip(clip);
Toast.makeText(context, "複制成功", Toast.LENGTH_LONG).show();
}
11.有EditText時候進入界面預設彈出輸入框
防止有EditText時候進入界面直接彈出輸入框,不友好
可以在EditText前面放置一個看不到的LinearLayout
<LinearLayout
android:focusable="true"
android:focusableInTouchMode="true"
android:layout_width="0px"
android:layout_height="0px"/>
或者在他的父布局中加入
android:focusable="true"
android:focusableInTouchMode="true"
即可
12.關于WebView的使用用到的問題
1.加載完顯示空白頁:
@Override public boolean shouldOverrideUrlLoading(WebView view, String url) {
CommUtil.logD(TAG, "shouldOverrideUrlLoading, url:" + url);
return false;
}
傳回false 就好了
2.webview 中加載頁面的對話框
如果需要彈出網頁的對話框之類的,需要設定如下
mWebView.setWebChromeClient(new WebChromeClient(){
@Override
public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
return super.onJsAlert(view, url, message, result);
}
});
13.android 6.0的權限的問題
android 6.0的手機就算manifest檔案中設定了存儲權限,app運作時候還是需要手動申請,否則在app裡面建立檔案夾會失敗。
需要 調用 showPremissDialogIfNeccessary 就好了
private static final int REQUEST_CODE_FOR_WRITE_PERMISSON = 1;
public void showPremissDialogIfNeccessary(){
//6.0 權限的手機需要打開權限
if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.M){
int hasWriteContactsPermission = checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE);
if(hasWriteContactsPermission != PackageManager.PERMISSION_GRANTED){
requestPermissions(new String[]{ Manifest.permission.WRITE_EXTERNAL_STORAGE }, REQUEST_CODE_FOR_WRITE_PERMISSON);
return;
}
}
}
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if(requestCode == REQUEST_CODE_FOR_WRITE_PERMISSON){
if(permissions[0].equals(Manifest.permission.WRITE_EXTERNAL_STORAGE) && grantResults[0] == PackageManager.PERMISSION_GRANTED){
//同意就情況
}else{
Toast.makeText(mContext, R.string.request_write_pression_failed, Toast.LENGTH_SHORT).show();
}
}
}
由于上述的方法中是在sdk 為 6.0 的方法存在的,這裡我們可以使用v4擴充包來幫助我們實作權限判斷,
ContextCompat.checkSelfPermission()
ActivityCompat.requestPermissions()
ActivityCompat.OnRequestPermissionsResultCallback
ActivityCompat.shouldShowRequestPermissionRationale()
首先這個activity 要實作 ActivityCompat.OnRequestPermissionsResultCallback方法,這樣就必須重寫onRequestPermissionsResult方法。
private static final int REQUEST_CODE_FOR_WRITE_PERMISSON = 1;
public void showPremissDialogIfNeccessary(){
//大于6.0 權限的手機需要打開權限
if(Build.VERSION.SDK_INT >= 23){
int hasWriteContactsPermission = ContextCompat.checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE);
if(hasWriteContactsPermission != PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(new String[]{ Manifest.permission.WRITE_EXTERNAL_STORAGE }, REQUEST_CODE_FOR_WRITE_PERMISSON);
return;
}
}
}
@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
if(requestCode == REQUEST_CODE_FOR_WRITE_PERMISSON){
if(permissions[0].equals(Manifest.permission.WRITE_EXTERNAL_STORAGE) && grantResults[0] == PackageManager.PERMISSION_GRANTED){
//同意
}else{
Toast.makeText(mContext, "擷取存儲權限失敗"), Toast.LENGTH_SHORT).show();
}
}
}
具體的可以參考這篇部落格
http://blog.csdn.net/kong_gu_you_lan/article/details/52488097
14.Listview的item最後一個不需要實作divider的樣式
關于Listview 的divider的設定問題,如果資料item最後一個不需要現實divider的樣式(分割線),需要将Listview 設定成wrap_content就好了(recyclerview不知道,有興趣的同學可以試一下)
15.删除圖檔後,從相冊選擇還是存在縮略圖
安卓圖庫都是在資料庫備份縮略圖的,删除原圖後,你需要去更新mediaprovider。在直行了File的delete方法後,其實縮略圖還在,現在要做的就是需要去更新資料庫删除縮略圖。
方法如下:
1.發廣播的方式
public void scanFileAsync(Context ctx, String filePath) {
Intent scanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
scanIntent.setData(Uri.fromFile(new File(filePath)));
ctx.sendBroadcast(scanIntent);
}
2.更新資料庫
getcontentresolver.delete(Media.EXTERNAL_CONTENT_URI, Media.DATA + "=?",path);