android studio开发小笔记1
1、点击空白处隐藏软键盘
/* 隐藏软键盘 * */ public boolean dispatchTouchEvent(MotionEvent ev) { if (ev.getAction() == MotionEvent.ACTION_DOWN) { View v = getCurrentFocus(); if (isShouldHideInput(v, ev)) { InputMethodManager imm = (InputMethodManager) getSystemService(Context.INPUT_METHOD_SERVICE); if (imm != null) { imm.hideSoftInputFromWindow(v.getWindowToken(), 0); } } return super.dispatchTouchEvent(ev); } if (getWindow().superDispatchTouchEvent(ev)) { return true; } return onTouchEvent(ev); } public boolean isShouldHideInput(View v, MotionEvent event) { if (v != null && (v instanceof EditText)) { int[] leftTop = { 0, 0 }; v.getLocationInWindow(leftTop); int left = leftTop[0]; int top = leftTop[1]; int bottom = top + v.getHeight(); int right = left + v.getWidth(); if (event.getX() > left && event.getX() < right && event.getY() > top && event.getY() < bottom) { } else { return true; } } return false; }
2、沉浸式状态栏
//设置沉浸式状态栏 android 4.4 及以上支持 if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) { //透明状态栏 getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS); //透明导航栏 getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION); }
3、设置导航栏
xml代码：
<android.support.v7.widget.Toolbar android:id="@+id/toolbar1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignParentLeft="true" android:layout_alignParentStart="true" android:layout_alignParentTop="true" android:background="#5caef9" android:minHeight="50dp" android:gravity="center" android:textAlignment="center" > </android.support.v7.widget.Toolbar>
后台代码：
//设置导航栏 Toolbar toolbar = (Toolbar)findViewById(R.id.toolbar1);//鑾峰彇椤甸潰鐨勫伐鍏锋爮 toolbar.setTitle("设置服务"); toolbar.setTitleMarginStart(370); toolbar.setTitleTextColor(Color.WHITE); toolbar.setTitleMarginTop(10); toolbar.setNavigationIcon(R.mipmap.allback); toolbar.setNavigationOnClickListener(new View.OnClickListener() { @Override public void onClick(View view) { Intent intent = new Intent(SettingServiceActivity.this,MyselfLoginActivity.class); startActivity(intent); } });
4、获取屏幕宽高和设置控件宽高
//设置输入框宽高 EditText tvservicepath = (EditText)findViewById(R.id.tvservicepath); tvservicepath.setText(R.string.serverpath);//获取资源文件 //获取屏幕高宽 WindowManager wm = (WindowManager) this.getSystemService(Context.WINDOW_SERVICE); DisplayMetrics dm = new DisplayMetrics(); wm.getDefaultDisplay().getMetrics(dm); int width = dm.widthPixels; // 屏幕宽度（像素） int height = dm.heightPixels; // 屏幕高度（像素） float density = dm.density; // 屏幕密度（0.75 / 1.0 / 1.5） int densityDpi = dm.densityDpi; // 屏幕密度dpi（120 / 160 / 240） // 屏幕宽度算法:屏幕宽度（像素）/屏幕密度 int screenWidth = (int) (width / density); // 屏幕宽度(dp) int screenHeight = (int) (height / density);// 屏幕高度(dp) ViewGroup.LayoutParams para; para = tvservicepath.getLayoutParams(); para.height = screenHeight/2; para.width = width-50; tvservicepath.setLayoutParams(para);
5、在手机本地保存数据和读取(参考：https://blog.csdn.net/acm_th/article/details/50009575)
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context="com.example.savedatademo.MainActivity" > <EditText android:id="@+id/input" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="请输入" /> <Button android:id="@+id/btn1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/input" android:text="保存数据" /> <Button android:id="@+id/btn2" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_below="@+id/btn1" android:text="读取数据"/> </RelativeLayout>
package com.example.savedatademo; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.PrintStream; import java.util.Scanner; import android.app.Activity; import android.os.Bundle; import android.view.Menu; import android.view.MenuItem; import android.view.View; import android.view.View.OnClickListener; import android.view.Window; import android.widget.Button; import android.widget.EditText; import android.widget.Toast; public class MainActivity extends Activity { private Button saveBtn = null; private Button readBtn = null; private EditText input = null; private final static String FILE_NAME = "xth.txt"; // 设置文件的名称 @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); requestWindowFeature(Window.FEATURE_NO_TITLE); setContentView(R.layout.activity_main); input = (EditText) findViewById(R.id.input); saveBtn = (Button) findViewById(R.id.btn1); readBtn = (Button) findViewById(R.id.btn2); saveBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { String data = input.getText().toString(); save(data); Toast.makeText(MainActivity.this, "保存数据成功！", Toast.LENGTH_SHORT) .show(); } }); readBtn.setOnClickListener(new OnClickListener() { @Override public void onClick(View v) { StringBuffer sb = read(); Toast.makeText(MainActivity.this, "读取数据为：" + sb, Toast.LENGTH_SHORT).show(); } }); } private StringBuffer read() { FileInputStream in = null; Scanner s = null; StringBuffer sb = new StringBuffer(); try { in = super.openFileInput(FILE_NAME); s = new Scanner(in); while (s.hasNext()) { sb.append(s.next()); } } catch (Exception e) { e.printStackTrace(); } return sb; } private void save(String data) { FileOutputStream out = null; PrintStream ps = null; try { out = super.openFileOutput(FILE_NAME, Activity.MODE_APPEND); ps = new PrintStream(out); ps.println(data); } catch (Exception e) { e.printStackTrace(); } finally { if (out != null) { try { out.close(); ps.close(); } catch (IOException e) { e.printStackTrace(); } } } } }
这是追加内容的，如果覆盖，改成：
out = super.openFileOutput(FILE_NAME, Activity.MODE_WORLD_WRITEABLE);
6、代码设置按钮被点击使用performClick（）方法。
7、设置控件的显示与隐藏：
View缺省为可见的，在应用可以通过setVisibility 修改View的可见性，
View.VISIBLE View可见，View.INVISIBLE View不可以见，但仍然占据可见时的大小和位置。
View.GONE View不可见，且不占据空间。
