Android基礎View回顧

為了提高工作效率，對一些常見View的特殊用法作一下總結。

一、進度條對話框

????? ?坑：https://blog.csdn.net/nailsoul/article/details/38870827?（ProgressBar占據位置但是不顯示的問題）

????????最近我的同事孫大姐提個需求：將進度顯示框的進度條放到文字上方。

????? ?1.使用系統的ProgressDialog

??????????https://www.cnblogs.com/guop/p/5139937.html? (圓形進度條與水平進度條) （注意構造方法要傳theme，否則有些手機可能看不到進度條。）

??????????看不到進度條的還有一種情況就是沒有指定ProgressBar的一個屬性：

?????

??????????

? ?

????????? 注意創建ProgressDialog時不要使用Builder來創建，即：

?????new?ProgressDialog.Builder(mContext).create();

????????? 用這種方式創建的ProgressDialog會不顯示進度條，只會顯示純文字。

? ? ? ? ? 原生的進度顯示框設置樣式為SPINNER，默認進度條放在文字左方，所以無法滿足孫大姐的需求。

???????

????????2.使用AlertDialog自定義View

????????? ?正確的用法：

?????progressDialog?=?new?AlertDialog.Builder(mContext).create();
?????View?rootView?=?LayoutInflater.from(mContext).inflate(R.layout.mprogress_dialog,?null);
?????pbBar?=?rootView.findViewById(R.id.pb_bar);
?????tvMsg?=?(TextView)?rootView.findViewById(R.id.tvMsg);

?????progressDialog.setView(rootView);

???????????注意錯誤的用法：

?????new?ProgressDialog.Builder(mContext,ProgressDialog.THEME_DEVICE_DEFAULT_DARK).create();

????????? 上面的ProgressDialog.Builder實際上還是父類AlertDialog的類，create出來的是AlertDialog，并非ProgressDialog，無法將AlertDialog強制轉換成ProgressDialog。

????????? ?也就無法使用ProgressDialog的特有方法progressDialog.setProgressStyle(ProgressDialog.STYLE_SPINNER)，因此，如果想通過Builder類創建的dialog來實現圓形進度條對話框，

????????? ?只有自定義view。

???????? 3.繼承的方式

? ? ? ? ? ? 方式1：直接繼承ProgressDialog

????????????研究ProgressDialog的源碼可以發現其onCreate方法里：

??????else{
????????????View?view?=?inflater.inflate(a.getResourceId(
????????????????????com.android.internal.R.styleable.AlertDialog_progressLayout,
????????????????????R.layout.progress_dialog),?null);
????????????mProgress?=?(ProgressBar)?view.findViewById(R.id.progress);
????????????mMessageView?=?(TextView)?view.findViewById(R.id.message);
????????????setView(view);
??????}

????????????注意上面的R是com.android.internal.R，如果將布局引用為自己應用的app不就行了。于是繼承ProgressDialog準備復寫onCreate方法：

????????????

????????????可以發現會報各種引用不到的問題，因為這些變量都是父類定義的private變量。

????????????對于變量mContext有public訪問方法

????????????

????????????對于其他沒有public訪問方法的private變量，該如何獲取呢？

????????????答案：反射? ?(代碼附于文章最后)

????????????

? ? ? ? ? ? 還有一項就是系統資源文件com.android.internal.R如何獲取呢？

????????????答案：反射? ?(代碼附于文章最后)

????????????com.android.internal.R是無法在java文件里import的

????????????

????????????將私有變量和方法用反射代替之后，代碼如下：

@Override
protected?void?onCreate(Bundle?savedInstanceState)?{
????????LayoutInflater?inflater?=?LayoutInflater.from(getContext());
????????TypedArray?a?=?getContext().obtainStyledAttributes(null,
????????????????SystemResourceManager.getResourceStyleableIds("AlertDialog"),
????????????????SystemResourceManager.getResourceAttrId("alertDialogStyle")
????????????????,?0);
????????if?((int)ReflectManger.getField(ProgressDialog.class,this,"mProgressStyle")??==?STYLE_HORIZONTAL)?{

????????/*?Use?a?separate?handler?to?update?the?text?views?as?they
?????????*?must?be?updated?on?the?same?thread?that?created?them.
?????????*/

????????????ReflectManger.setField(ProgressDialog.class,this,"mViewUpdateHandler",new?Handler()?{
????????????????@Override
????????????????public?void?handleMessage(Message?msg)?{
????????????????????super.handleMessage(msg);

????????????????/*?Update?the?number?and?percent?*/
????????????????????int?progress?=?((ProgressBar)(ReflectManger.getField(ProgressDialog.class,this,"mProgress"))).getProgress();
????????????????????int?max?=?((ProgressBar)(ReflectManger.getField(ProgressDialog.class,this,"mProgress"))).getMax();
????????????????????if?(ReflectManger.getField(ProgressDialog.class,this,"mProgressNumberFormat")?!=?null)?{
????????????????????????String?format?=?(String)?ReflectManger.getField(ProgressDialog.class,this,"mProgressNumberFormat");
????????????????????????((TextView)ReflectManger.getField(ProgressDialog.class,this,"mProgressNumber")).setText(String.format(format,?progress,?max));
????????????????????}?else?{
????????????????????????((TextView)ReflectManger.getField(ProgressDialog.class,this,"mProgressNumber")).setText("");
????????????????????}
????????????????????if?(ReflectManger.getField(ProgressDialog.class,this,"mProgressPercentFormat")?!=?null)?{
????????????????????????double?percent?=?(double)?progress?/?(double)?max;
????????????????????????SpannableString?tmp?=?new?SpannableString(((NumberFormat)ReflectManger.getField(ProgressDialog.class,this,"mProgressPercentFormat")).format(percent));
????????????????????????tmp.setSpan(new?StyleSpan(android.graphics.Typeface.BOLD),
????????????????????????????????0,?tmp.length(),?Spannable.SPAN_EXCLUSIVE_EXCLUSIVE);
????????????????????????((TextView)ReflectManger.getField(ProgressDialog.class,this,"mProgressPercent")).setText(tmp);
????????????????????}?else?{
????????????????????????((TextView)ReflectManger.getField(ProgressDialog.class,this,"mProgressPercent")).setText("");
????????????????????}
????????????????}
????????????});

????????????View?view?=?inflater.inflate(a.getResourceId(
????????????????????SystemResourceManager.getResourceStyleableId("AlertDialog_horizontalProgressLayout"),
????????????????????SystemResourceManager.getResourceLayoutId("alert_dialog_progress")),?null);

????????????ReflectManger.setField(ProgressDialog.class,this,"mProgress",
?????????????????????view.findViewById(SystemResourceManager.getResourceId("progress"))
????????????????????);

????????????ReflectManger.setField(ProgressDialog.class,this,"mProgressNumber",
???????????????????view.findViewById(SystemResourceManager.getResourceId("progress_number"))
????????????);

????????????ReflectManger.setField(ProgressDialog.class,this,"mProgressPercent",
???????????????????view.findViewById(SystemResourceManager.getResourceId("progress_percent"))
????????????);
????????????setView(view);
????????}?else?{
????????????View?view?=?inflater.inflate(a.getResourceId(
????????????????????SystemResourceManager.getResourceStyleableId("AlertDialog_progressLayout"),
????????????????????R.layout.m_progress_dialog),?null);

????????????//注意布局中id的引用：android:id="@android:id/progress"
????????????ReflectManger.setField(ProgressDialog.class,this,"mProgress",
?????????????????????view.findViewById(android.R.id.progress)
????????????);
????????????ReflectManger.setField(ProgressDialog.class,this,"mMessageView",
?????????????????????view.findViewById(R.id.message)
????????????);

????????????setView(view);
????????}
????????a.recycle();

????????if?((int)ReflectManger.getField(ProgressDialog.class,this,"mMax")?>?0)?{
????????????setMax((int)ReflectManger.getField(ProgressDialog.class,this,"mMax")?);
????????}

????????if?((int)ReflectManger.getField(ProgressDialog.class,this,"mProgressVal")?>?0)?{
????????????setProgress((int)ReflectManger.getField(ProgressDialog.class,this,"mProgressVal")?);
????????}

????????if?((int)ReflectManger.getField(ProgressDialog.class,this,"mSecondaryProgressVal")?>?0)?{
????????????setSecondaryProgress((int)ReflectManger.getField(ProgressDialog.class,this,"mSecondaryProgressVal")?);
????????}

????????if?((int)ReflectManger.getField(ProgressDialog.class,this,"mIncrementBy")?>?0)?{
????????????incrementProgressBy((int)ReflectManger.getField(ProgressDialog.class,this,"mIncrementBy")?);
????????}

????if?((int)ReflectManger.getField(ProgressDialog.class,this,"mIncrementSecondaryBy")?>?0)?{
????????incrementSecondaryProgressBy((int)ReflectManger.getField(ProgressDialog.class,this,"mIncrementSecondaryBy")?);
????}

????if?(?ReflectManger.getField(ProgressDialog.class,this,"mProgressDrawable")?!=?null)?{
????????setProgressDrawable((Drawable)?ReflectManger.getField(ProgressDialog.class,this,"mProgressDrawable"));
????}
????if?(?ReflectManger.getField(ProgressDialog.class,this,"mIndeterminateDrawable")?!=?null)?{
????????setIndeterminateDrawable((Drawable)?ReflectManger.getField(ProgressDialog.class,this,"mIndeterminateDrawable"));
????}

????if?(?ReflectManger.getField(ProgressDialog.class,this,"mMessage")?!=?null)?{
????????setMessage((CharSequence)?ReflectManger.getField(ProgressDialog.class,this,"mMessage"));
????}

????setIndeterminate((Boolean)?ReflectManger.getField(ProgressDialog.class,this,"mIndeterminate"));
????try?{
????????ReflectManger.invokeMethod(ProgressDialog.class,this,"onProgressChanged",null,null);
????}?catch?(NoSuchMethodException?e)?{
????????e.printStackTrace();
????}?catch?(InvocationTargetException?e)?{
????????e.printStackTrace();
????}?catch?(IllegalAccessException?e)?{
????????e.printStackTrace();
????}
????super.onCreate(savedInstanceState);
}

?????????自定義布局m_progress_dialog.xml??如下：

????<FrameLayout?xmlns:android="http://schemas.android.com/apk/res/android"
????????android:layout_width="match_parent"
????????android:layout_height="wrap_content">
????
????????<LinearLayout?android:id="@+id/body"
????????????android:orientation="horizontal"
????????????android:layout_width="match_parent"
????????????android:layout_height="match_parent"
????????????android:baselineAligned="false"
????????????android:paddingStart="8dip"
????????????android:paddingTop="10dip"
????????????android:paddingEnd="8dip"
????????????android:paddingBottom="10dip">
????
????????????<ProgressBar?android:id="@android:id/progress"
????????????????
????????????????android:layout_width="wrap_content"
????????????????android:layout_height="wrap_content"
????????????????android:max="10000"
????????????????android:layout_marginEnd="12dip"?/>
????
????????????<TextView?android:id="@+id/message"
????????????????android:layout_width="match_parent"
????????????????android:layout_height="wrap_content"
????????????????android:layout_gravity="center_vertical"?/>
????????</LinearLayout>
?????</FrameLayout>

??????????但是復寫的onCreate方法中有個問題

?????????view.findViewById(R.id.message)

??? ? ? ? ?結果返回null，但是這個id明明是存在的。但是view.findViewById(android.R.id.progress)怎么不是null呢？

????????? ?思考半天，看下面的代碼：
? ?????????

??View?view?=?inflater.inflate(a.getResourceId(
????????????????????SystemResourceManager.getResourceStyleableId("AlertDialog_progressLayout"),
????????????????????R.layout.m_progress_dialog),?null);

????????? ?R.layout.m_progress_dialog只是一個備用布局，跟本就沒有加載進去。

????????? ?將上面的代碼稍作修改，將getResourceId方法的第一個值傳入一個非法參數0（-1試了不行），這樣R.layout.m_progress_dialog就加載了，果然一切正常。

View?view?=?inflater.inflate(a.getResourceId(
//????????????????????????SystemResourceManager.getResourceStyleableId("AlertDialog_progressLayout"),
????????????????????????0,
????????????????????????R.layout.m_progress_dialog),?null);

? ? ? ? ? ?但是圓形進度條不會顯示，上面已經說到了，構造方法要傳theme，但是傳了theme之后，上面代碼又會報下面的錯：

????????????android.content.res.Resources$NotFoundException: File res/drawable-xhdpi-v4/dialog_full_holo_light.9.png from xml type layout resource ID #0x1080295

? ? ? ? ? ? 通過debug發現，如果Dialog構造方法加了主題，resId ！=?R.layout.m_progress_dialog

????????????

????????????如果Dialog構造方法不加主題?，

一-2、SeekBar

• ?自定義樣式

  https://blog.csdn.net/u010029983/article/details/45222257? ?（推薦）
  

  https://blog.csdn.net/qq_38407076/article/details/83012684

  改變游標圖片大?。篽ttps://www.cnblogs.com/welhzh/p/3711694.html

• 
  

????????????

二、快速創建一個輸入框

??Builder?builder?=?new?Builder();
????builder.setTitle(title)
????????????.setMessage(message);
????final?EditText?et?=?new?EditText(builder.getContext());
????et.setInputType(InputType.TYPE_CLASS_TEXT?|?InputType.TYPE_TEXT_VARIATION_PASSWORD);
????builder.setView(et);

?????? 注意動態設置edittext的inputType為密碼輸入框為：

????InputType.TYPE_CLASS_TEXT?|?InputType.TYPE_TEXT_VARIATION_PASSWORD

?

三、Spinner

• ?快速創建spinner

  
  

• private?void?initAreaSpinner(Spinner?spinner_area)?{
  ????ArrayAdapter<CharSequence>?adapter;
  ????adapter?=?ArrayAdapter.createFromResource(this,?R.array.area,?android.R.layout.simple_spinner_item);
  ????spinner_area.setAdapter(adapter);
  ????spinner_area.setOnItemSelectedListener(new?AdapterView.OnItemSelectedListener()?{
  ????????@Override
  ????????public?void?onItemSelected(AdapterView<?>?parent,?View?view,?int?position,?long?id)?{
  ????????????switch?(position){
  ????????????????case?0:
  ????????????????????sdk.setBleAreaType(BleAreaType.HENAN);
  ????????????????????break;
  ????????????????case?1:
  ????????????????????sdk.setBleAreaType(BleAreaType.GUIZHOU);
  ????????????????????break;
  ????????????????case?2:
  ????????????????????sdk.setBleAreaType(BleAreaType.GUANGXI);
  ????????????????????break;
  ????????????}
  ????????}
  
  ????????@Override
  ????????public?void?onNothingSelected(AdapterView<?>?parent)?{
  
  ????????}
  ????});
  ????spinner_area.setSelection(0);
  }

• ? ?? ?
  

四、PopWindow

????? ?https://github.com/pinguo-zhouwei/CustomPopwindow?(超級方便好用的popwindow)

????????

五、NavigationView

????????1.修改NavigationView中的Item的Icon大小

????????????https://blog.csdn.net/zuolovefu/article/details/50175245

????????2.Android NavigationView 中 menu item 字體大小設置

????????????https://blog.csdn.net/TLD_DLT/article/details/79865525

六、TabLayout

???????? 1.修改字體大小

????????????https://blog.csdn.net/qq_33919497/article/details/78548198

???????? 2.