Android 笔记 6

目录

一个游戏，未完，待续

fragment

碎片的生命周期

给碎片创建布局，创建碎片

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    android:orientation="vertical" android:layout_width="match_parent"    android:layout_height="match_parent">    <ImageView        android:id="@+id/fragment_test"        android:layout_width="match_parent"        android:layout_height="match_parent"        android:src="@mipmap/msg"        android:scaleType="fitXY"        /></LinearLayout>package com.example.linj.fragmentapplication.fragment;import android.os.Bundle;import android.support.annotation.Nullable;import android.support.v4.app.Fragment;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.Button;import android.widget.Toast;import com.example.linj.fragmentapplication.R;/** * Created by Administrator on 2015/9/6. */public class TestFragment extends Fragment {    @Nullable    @Override    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {        View view = inflater.inflate(R.layout.test_fragment_lyout, null);        return view;    }}//在活动中加载碎片，活动和碎片之间的通信通过fragmentManager fragmentManager = getSupportFragmentManager();//在碎片中则通过getActivity与活动通信

数据存储之文件存储，sharedPreferences

文件存储和sharedPreference存储
在布局文件中新建几个按钮和一个edittext，一个textview简单实现存储的读出和写入

package com.example.linj.myapplication;import android.content.SharedPreferences;import android.os.Environment;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.Menu;import android.view.MenuItem;import android.view.View;import android.widget.Button;import android.widget.EditText;import android.widget.TextView;import java.io.BufferedInputStream;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.io.PrintWriter;public class MainActivity extends AppCompatActivity implements View.OnClickListener{    private EditText mEditText;    private Button mButtonWrite;    private Button mButtonRead;    private TextView mTextShow;    private SharedPreferences preferences;    private Button mButtonWriteCache;    private Button mButtonReadCache;    private File file;    private Button mButtonSdcard;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        mEditText = (EditText) findViewById(R.id.edit_shared);        mTextShow = (TextView) findViewById(R.id.text_show);        mButtonWrite = (Button) findViewById(R.id.button_write);        mButtonRead = (Button) findViewById(R.id.button_read);        mButtonWriteCache = (Button) findViewById(R.id.write_cache);        mButtonReadCache = (Button) findViewById(R.id.read_cache);        mButtonSdcard = (Button) findViewById(R.id.sdcard);        mButtonWrite.setOnClickListener(this);        mButtonRead.setOnClickListener(this);        mButtonWriteCache.setOnClickListener(this);        mButtonReadCache.setOnClickListener(this);        mButtonSdcard.setOnClickListener(this);    }    @Override    public void onClick(View v) {//        preferences = getPreferences( MODE_PRIVATE);        preferences = getSharedPreferences("someInformation", MODE_PRIVATE);        switch (v.getId()) {            case R.id.button_write:                try {                    String text = mEditText.getText().toString();                    FileOutputStream os = openFileOutput("cache",MODE_PRIVATE);                    PrintWriter writer = new PrintWriter(new OutputStreamWriter(os));                    writer.write(text);                    writer.flush();                    writer.close();                    os.close();                } catch (FileNotFoundException e) {                    e.printStackTrace();                } catch (IOException e) {                    e.printStackTrace();                }//                SharedPreferences.Editor editor = preferences.edit();//                editor.putString("key", mEditText.getText().toString());//                editor.commit();                mEditText.setText("");                break;            case R.id.button_read:                String text = preferences.getString("key", "错误");                mTextShow.setText(text);                break;            case R.id.write_cache:                String text2 = mEditText.getText().toString();                file = new File(getCacheDir(),"helloWorld");                if (!file.exists()){                    try {                        file.createNewFile();                    } catch (IOException e) {                        e.printStackTrace();                    }                }                try {                    FileOutputStream outputStream = new FileOutputStream(file);                    PrintWriter writer = new PrintWriter(new OutputStreamWriter(outputStream));                    writer.write(text2);                    writer.flush();                    writer.close();                    outputStream.close();                } catch (FileNotFoundException e) {                    e.printStackTrace();                } catch (IOException e) {                    e.printStackTrace();                }                break;            case R.id.read_cache:                try {                    FileInputStream inputStream = new FileInputStream(file);                    BufferedReader br = new BufferedReader(new InputStreamReader(inputStream));                    String line = br.readLine();                    while(line !=null){                        mTextShow.setText(line);                        line = br.readLine();                    }                } catch (FileNotFoundException e) {                    e.printStackTrace();                } catch (IOException e) {                    e.printStackTrace();                }                break;            case R.id.sdcard:                String text3 = mEditText.getText().toString();                File file = new File(Environment.getExternalStorageDirectory().getAbsolutePath(),"abc");                if (!file.exists()){                    try {                        file.createNewFile();                    } catch (IOException e) {                        e.printStackTrace();                    }                }                try {                    FileOutputStream outputStream = new FileOutputStream(file);                    PrintWriter writer = new PrintWriter(new OutputStreamWriter(outputStream));                    writer.write(text3);                    writer.flush();                    writer.close();                    outputStream.close();                } catch (FileNotFoundException e) {                    e.printStackTrace();                } catch (IOException e) {                    e.printStackTrace();                }                break;            default:                break;        }    }}

Android的最重要的存储方式，数据库存储，还有网络存储等等下次再一起写

总结

我好像又忘了写注释了，罪过罪过，没有下次了，代码规范是编程永恒不变的要求，切记切记！边学习，边记录，见证菜鸟的成长之路。