小编Chi*_*oni的帖子

ScrollView和NestedScrollView实际有什么区别？我用过他们两个.两者都延伸了FrameLayout.我想深入了解他们两人的利弊.如果有人可以请帮助我.谢谢.

我想知道使用BaseAdapter和之间的区别ArrayAdapter.

我一直在实现我想要的东西ArrayAdapters.

它是否会影响ListView实现它的适配器接口的性能？

而且,最后一个问题是,我能否实现ListView使用其中任何一项所做的任何事情Adapters,或者,在某些情况下,只能使用特定的适配器？

因此,从升级build.gradle(Project)后运行项目时出现以下错误

dependencies {
        classpath 'com.android.tools.build:gradle:2.0.0-alpha2'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
}

至

dependencies {
        classpath 'com.android.tools.build:gradle:2.0.0-alpha3'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
}

我刚刚从改变gradle这个2.0.0-alpha2来2.0.0-alpha3,然后,力图打造该项目.

错误日志:

Information:Gradle tasks [:app:assembleDebug]
:app:incrementalDebugBuildInfoGenerator
:app:preBuild UP-TO-DATE
:app:preDebugBuild
:app:checkDebugManifest
:app:preReleaseBuild UP-TO-DATE
:app:prepareComAndroidSupportAppcompatV72311Library UP-TO-DATE
:app:prepareComAndroidSupportCardviewV72311Library UP-TO-DATE
:app:prepareComAndroidSupportCustomtabs2311Library UP-TO-DATE
:app:prepareComAndroidSupportDesign2311Library UP-TO-DATE
:app:prepareComAndroidSupportRecyclerviewV72311Library UP-TO-DATE
:app:prepareComAndroidSupportSupportV42311Library UP-TO-DATE
:app:prepareComDigitsSdkAndroidDigits192Library UP-TO-DATE
:app:prepareComTwitterSdkAndroidTweetComposer102Library UP-TO-DATE …

我开始使用DataBinding功能了.我面临着问题.

错误:(21,9)错误:找不到符号类ContactListActivityBinding

build.gradle(模块:app)

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.2"

    defaultConfig {
        applicationId "com.letsnurture.ln_202.databindingdemo"
        minSdkVersion 15
        targetSdkVersion 23
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    dataBinding {
        enabled = true
    }
}

dependencies {
    compile fileTree(dir: 'libs', include: ['*.jar'])
    testCompile 'junit:junit:4.12'
    compile 'com.android.support:appcompat-v7:23.1.1'
    compile 'com.android.support:design:23.1.1'
}

ContactListActivity.java

import android.databinding.DataBindingUtil;
import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;

import com.letsnurture.ln_202.databindingdemo.model.Contact; …

很高兴知道java 在Java版本8中引入了Lambda表达式.

我在android studio工作.我注意到它DialogInterface.OnClickListener()显示下划线并变成灰色,如下所示:

所以,我alter + enter在那一行上找到了用Lambda Expressions替换代码的选项,如下所示:

结果如下:

运行代码后,它显示了这个错误:

错误:(160,69)错误:-source 1.7不支持lambda表达式(使用-source 8或更高版本启用lambda表达式)

但我已经在使用java了jdk1.8.0_31.还有什么我需要安装吗？

任何人都可以帮我解决..

我有一个小问题,但不明白如何摆脱这个.

我创建了一个用于提供通知的类,但这些行被标记为已弃用:

...
Notification notification = new Notification(icon, text, time); // deprecated in API level 11
...
notification.setLatestEventInfo(this, title, text, contentIntent); // deprecated in API level 11
...

替代方法是:

...
Notification noti = new Notification.Builder(mContext)
         .setContentTitle("New mail from " + sender.toString())
         .setContentText(subject)
         .setSmallIcon(R.drawable.new_mail)
         .setLargeIcon(aBitmap)
         .build(); // available from API level 11 and onwards
...

我可以编写类似的代码:

if(API_level < 11)
{
...
    Notification notification = new Notification(icon, text, time); // deprecated in API level 11
    ...
    notification.setLatestEventInfo(this, title, text, contentIntent); // deprecated …

我想在我的应用程序中只运行一段代码,并且是第一次运行它时(新安装的应用程序).我怎么能这样做,任何人都可以解释给出一段代码.

实际上,在我的android项目中,我想创建数据库并在第一次运行时插入一些值.之后,该特定代码不应该再次运行.如何通过SharedPreferences或Preferences实现此机制.

示例代码将更有帮助.

Facebook SDK版本4.27.0

Android OS 8.0版

应用程序崩溃异常,这是我在Crashlytics上找到的跟踪日志:

Fatal Exception: java.lang.RuntimeException: Unable to start activity ComponentInfo{com.xxx.yyy/com.facebook.FacebookActivity}: java.lang.IllegalStateException: Only fullscreen opaque activities can request orientation
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2822)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2897)
       at android.app.ActivityThread.-wrap11(Unknown Source)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1598)
       at android.os.Handler.dispatchMessage(Handler.java:105)
       at android.os.Looper.loop(Looper.java:251)
       at android.app.ActivityThread.main(ActivityThread.java:6563)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
Caused by java.lang.IllegalStateException: Only fullscreen opaque activities can request orientation
       at android.app.Activity.onCreate(Activity.java:986)
       at android.support.v4.app.SupportActivity.onCreate(SupportActivity.java:66)
       at android.support.v4.app.FragmentActivity.onCreate(FragmentActivity.java:285)
       at com.facebook.FacebookActivity.onCreate(FacebookActivity.java:62)
       at android.app.Activity.performCreate(Activity.java:6975)
       at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1214)
       at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2775)
       at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2897)
       at android.app.ActivityThread.-wrap11(Unknown Source)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1598)
       at android.os.Handler.dispatchMessage(Handler.java:105)
       at android.os.Looper.loop(Looper.java:251) …

我工作的一个应用程序,它可以运行在Froyo和JellyBean.我有一个扩展PageTransformer的类,如下所示:

import android.support.v4.view.ViewPager.PageTransformer;
import android.view.View;

public class ZoomOutPageTransformer implements PageTransformer {
    private static float MIN_SCALE = 0.85f;
    private static float MIN_ALPHA = 0.5f;

    public void transformPage(View view, float position) {
        int pageWidth = view.getWidth();
        int pageHeight = view.getHeight();

        if (position < -1) { 
            view.setAlpha(0);

        } else if (position <= 1) { 
            float scaleFactor = Math.max(MIN_SCALE, 1 - Math.abs(position));
            float vertMargin = pageHeight * (1 - scaleFactor) / 2;
            float horzMargin = pageWidth * (1 - scaleFactor) …

所以,我有以下代码打开相机,捕获图像并将其保存在SDCard上.

public void getPhotoFromCamera() {
    Intent takePictureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
    File mediaStorageDir = new File(
            Environment.getExternalStorageDirectory()
                    + File.separator
                    + getString(R.string.directory_name_corp_chat)
                    + File.separator
                    + getString(R.string.directory_name_temp)
    );

    if (!mediaStorageDir.exists()) {
        mediaStorageDir.mkdirs();
    }

    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss",
            Locale.getDefault()).format(new Date());
    try {
        mediaFile = File.createTempFile(
                "TEMP_FULL_IMG_" + timeStamp,
                ".jpg",
                mediaStorageDir
        );
        takePictureIntent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(mediaFile));
        startActivityForResult(takePictureIntent, PICK_FROM_CAMERA);
    } catch (IOException e) {
        e.printStackTrace();
    }
}

private void performCrop(Uri picUri) {
    try {
        Intent cropIntent = new Intent("com.android.camera.action.CROP");
        cropIntent.setDataAndType(picUri, "image/*");
        cropIntent.putExtra("crop", "true");
        cropIntent.putExtra("aspectX", 1);
        cropIntent.putExtra("aspectY", 1); …