开发笔记

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1. 颜色值计算



2. 逆向助手反编译，apktool, jd-gui,dex2jar-0.0.9.15

3. 设置图片底色: ImageView.setColorFilter()

4. 打log

StackTraceElement st[] = Thread.currentThread().getStackTrace();

for (int i = 0; i < st.length; i++) {

android.util.Log.i("silion", "trace: " + st[i].toString());

}

android.util.Log.i("silion", "--------boundary--------");

5. 卡顿时，连续onClick，同时add多个Fragment

FragmentTransaction.commitAllowingStateLoss();

FragmentManager.executePendingTransactions();

6. 文字带下划线

Strings

<resources>
<string name="hello"><u>phone: 1390123456</u></string>
<string name="app_name">MyLink</string>
</resources>

Code

TextView textView = (TextView)findViewById(R.id.testView);
textView.setText(Html.fromHtml("<u>"+"hahaha"+"</u>"));

7. EditText 去掉下划线

android：background="@null"

8. String添加文字

<string name="hello">你好，我是%1$s。</string>

String.format(context.getString(R.id.hello), "silion")

9. 判断字符串是否为空(去掉首尾空格)

TextUtils.isEmpty(string.trim())

10. String中的部分文字设置成超链接

a. strings.xml

<string name="silion_blog">这是<a href = "http://blog.csdn.net/xilove102">silion</a>的博客</string>

b. java中实现

TextView hyperlinkTextView = new TextView(this);
hyperlinkTextView.setText(Html.fromHtml(getResources().getString(R.string.silion_blog)));
hyperlinkTextView.setMovementMethod(LinkMovementMethod.getInstance());

11. 隐藏输入法

InputMethodManager imm = (InputMethodManager) this.getSystemService(Context.INPUT_METHOD_SERVICE);
if (imm != null) {
imm.hideSoftInputFromWindow(hyperlinkTextView.getWindowToken(), 0);
}

12. 自定义ListView divider
drawable/divider_listitem.xml

<insert xmlns:android=“http://schemas.android.com/apk/res/android"
android:insert="0dp">

<shape android:shape="rectangle">
<solid android:color="@color/ca" />
</shape>
</insert>

布局

<ListView
android:id="@+id/listView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:divider="@drawable/divider_listitem"
android:dividerHeight="2px" />

13. Android API Level 8及其以上Android系统提供了为应用程序数据的备份和恢复功能

android:allowBackup="true"

14. Call requires API level 18 (current min is 14):类似异常解决



15. actionLink to URI

Log.d(TAG, "performActionLink, actionLink = " + "voc://view/main");

URI uri = null;
try {
uri = new URI(actionLink.trim());
} catch (URISyntaxException e) {
Log.e(TAG, e.getMessage(), e);
}
if (uri == null) {
return;
}

String scheme = uri.getScheme() != null ? uri.getScheme() : "";
String function = uri.getHost() != null ? uri.getHost() : "";
String path = uri.getPath() != null ? uri.getPath() : "";
if (path.length() > 1) {
path = path.substring(1);
}

16. 字符串格式化String.format()

res\valuse\strings.xml

<string name="string_format">字符串格式化 数字：%1$d</string>

MainFragment.java

titleTextView.setText(String.format(mMainActivity.getString(R.string.string_format), 0));

17. 定时重复执行 Timer() and TimerTask

mViewPagerScrollTimer = new Timer();
mViewPagerScrollTimer.scheduleAtFixedRate(new TimerTask() {
@Override
public void run() {
mHandler.post(new Runnable() {
@Override
public void run() {
int i = mHeaderViewPager.getCurrentItem() + 1;
if (i >= mHeaderViewPagerAdapter.getCount()) {
i = 0;
}

android.util.Log.v("slong.liang", "set current item = " + i);
mHeaderViewPager.setCurrentItem(i);
if (i == 0) {
//TODO changeNormalHeaderImage();
}
}
});
}
}, 5000, 5000);

18. 字符串编码转换

new String(str.getBytes("iso8859-1"), "utf-8")

19.URL编码

URLEncode.encode(str, "UTF-8")

20. Cannot merge new index 65539 into a non-jumbo instruction!

:app:dexDebugUnknown source file : UNEXPECTED TOP-LEVEL EXCEPTION:

Unknown source file : com.android.dex.DexIndexOverflowException: Cannot merge new index 65539 into a non-jumbo instruction!

defaultConfig {
applicationId "com.samsung.android.voc"
minSdkVersion 19
targetSdkVersion 23

// Enabling multidex support.
multiDexEnabled true
}

</pre><pre code_snippet_id="1687924" snippet_file_name="blog_20160518_20_6479886" name="code" class="plain">
dependencies {
    compile 'com.android.support:multidex:1.0.0'
}

21. finished with non-zero exit value 3

FAILURE: Build failed with an exception.

* What went wrong:

Execution failed for task ':app:dexDebug'.

> com.android.ide.common.process.ProcessException: org.gradle.process.internal.ExecException: Process 'command '/usr/lib/jvm/openjdk-7u55/bin/java'' finished with non-zero exit value 3

dexOptions {
javaMaxHeapSize "4g"
}

22. 获取状态栏高度

/**
* 用于获取状态栏的高度。
*
* @return 返回状态栏高度的像素值。
*/
private int getStatusBarHeight() {
if (mStatusBarHeight == 0) {
try {
Class<?> clazz = Class.forName("com.android.internal.R$dimen");
Object object = clazz.newInstance();
Field field = clazz.getField("status_bar_height");
int x = (int) field.get(object);
mStatusBarHeight = getResources().getDimensionPixelSize(x);
} catch (Exception e) {
e.printStackTrace();
}
}
return 0;
}

23. 设置Gradle

Use default gradle wrapper



在Android Studio系列教程一–下载与安装中新建项目成功后会下载Gradle，貌似这个过程不翻墙也是可以下载，但是访问特别慢，建议翻墙下载。那么下载的Gradle到什么地方呢？<
4000
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Mac上会默认下载到 **/Users/<用户名>/.gradle/wrapper/dists** 目录

Win平台会默认下载到 C:\Documents and Settings<用户名>.gradle\wrapper\dists 目录

你会看到这个目录下有个 gradle-x.xx-all 的文件夹, 如果下载实在太慢，但是又不想翻墙的话，可以自己手动到Gradle官网下载对应的版本，然后将下载的.zip文件(也可以解压)复制到上述的gradle-x.xx-all 文件夹下，不过还是建议让它直接下载的好。

版本不对错误：

Error:Gradle version 2.2 is required. Current version is 2.10. If using the gradle wrapper, try editing the distributionUrl in D:\05_Workspace\AndroidStudio\zhbj\gradle\wrapper\gradle-wrapper.properties to gradle-2.2-all.zip.

Please fix the project's Gradle settings.
<a href="createGradleWrapper">Migrate to Gradle wrapper and sync project</a><br><a href="openGradleSettings">Gradle settings</a>

有两种方法解决：

1. 修改gradle-wrapper.properties



2.修改build.gradle -- 如果不知道版本，可以新建一个hellowrod查看



24. SDK闪退问题：

修改F:\03_AndroidDev\sdk\tools\android.bat为：

rem Check we have a valid Java.exe in the path.
set java_exe=C:\Program Files\Java\jdk1.8.0_60\bin\java.exe
rem call lib\find_java.bat
rem if not defined java_exe goto :EOF

25. 显示布局边界