Nine_Patch圖片：一種被特殊處理過的圖片，能夠制定哪些區(qū)域可以被拉伸，哪些區(qū)域不可以
- 在Android Studio中使用.9圖很簡單：直接將圖片名稱以”.9.png”結(jié)束他嚷。
使用.9圖必須注意一點：文件的后綴名必須是.9.png，不能是.png或者是.9.png.png芭毙，這樣的命名都會導(dǎo)致編譯失敗筋蓖。- 命名完成后雙擊圖片即可進(jìn)行編輯
點九圖02.gif
第一步：創(chuàng)建項目導(dǎo)入圖片
第二步：創(chuàng)建界面布局文件
注：這里因為用到RecyclerView所以要先天際啊RecyclerView相關(guān)庫的依賴。
<?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"
android:background="#d8e0e8"
>
<android.support.v7.widget.RecyclerView
android:id="@+id/msg_recycler_view"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1">
</android.support.v7.widget.RecyclerView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content">
<EditText
android:id="@+id/input_text"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:layout_marginBottom="0dp"
android:hint="請輸入信息"
android:maxLines="2"/>
<Button
android:id="@+id/send"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="Send"/>
</LinearLayout>
</LinearLayout>
第三步：創(chuàng)建信息窗口布局文件
<?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="wrap_content"
android:padding="10dp">
<LinearLayout
android:id="@+id/left_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="left"
android:background="@drawable/message_left">
<TextView
android:id="@+id/left_msg"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="10dp"
android:textColor="#fff"/>
</LinearLayout>
<LinearLayout
android:id="@+id/right_layout"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="right"
android:background="@drawable/message_right">
<TextView
android:id="@+id/right_msg"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center"
android:layout_margin="10dp" />
</LinearLayout>
</LinearLayout>
第四步：創(chuàng)建信息實體類
package com.example.anwser_mac.uibestpractice;
/**
* Created by anwser_mac on 2017/4/1.
*/
public class Msg {
public static final int TYPE_RECEIVED = 0;
public static final int TYPE_SENT = 1;
private String content;
private int type;
public Msg(String content, int type) {
this.content = content;
this.type = type;
}
public String getContent() {
return content;
}
public int getType() {
return type;
}
}
第五步：自定義RecyclerView適配器
package com.example.anwser_mac.uibestpractice;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.List;
/**
* Created by anwser_mac on 2017/4/1.
*/
public class MsgAdapter extends RecyclerView.Adapter<MsgAdapter.Viewholder> {
private List<Msg> mMsgList;
static class Viewholder extends RecyclerView.ViewHolder {
android.widget.LinearLayout leftLayout;
android.widget.LinearLayout rightLayout;
TextView leftMsg;
TextView rightMsg;
public Viewholder(View view) {
super(view);
leftLayout = (LinearLayout) view.findViewById(R.id.left_layout);
rightLayout = (LinearLayout) view.findViewById(R.id.right_layout);
leftMsg = (TextView) view.findViewById(R.id.left_msg);
rightMsg = (TextView) view.findViewById(R.id.right_msg);
}
}
public MsgAdapter(List<Msg> msgList) {
mMsgList = msgList;
}
@Override
public MsgAdapter.Viewholder onCreateViewHolder(ViewGroup parent, int viewType) {
View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.msg_item,parent,false);
return new Viewholder(view);
}
@Override
public void onBindViewHolder(MsgAdapter.Viewholder holder, int position) {
Msg msg = mMsgList.get(position);
if (msg.getType() == Msg.TYPE_RECEIVED) {
//如果是收到的消息退敦，則顯示在左邊的消息布局粘咖，將右邊的消息布局隱藏
holder.leftLayout.setVisibility(View.VISIBLE);
holder.rightLayout.setVisibility(View.GONE);
holder.leftMsg.setText(msg.getContent());
} else if(msg.getType() == Msg.TYPE_SENT) {
//如果是發(fā)出的消息，則顯示在右邊的消息布局苛聘，將左邊的消息布局隱藏
holder.rightLayout.setVisibility(View.VISIBLE);
holder.leftLayout.setVisibility(View.GONE);
holder.rightMsg.setText(msg.getContent());
}
}
@Override
public int getItemCount() {
return mMsgList.size();
}
}
第六步：加載數(shù)據(jù)
package com.example.anwser_mac.uibestpractice;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private List<Msg> msgList = new ArrayList<>();
private EditText inputText;
private Button send;
private RecyclerView msgRecyclerView;
private MsgAdapter adapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.layout);
//初始化消息數(shù)據(jù)
initMsgs();
inputText = (EditText) findViewById(R.id.input_text);
send = (Button) findViewById(R.id.send);
msgRecyclerView = (RecyclerView) findViewById(R.id.msg_recycler_view);
LinearLayoutManager layoutManager = new LinearLayoutManager(this);
msgRecyclerView.setLayoutManager(layoutManager);
adapter = new MsgAdapter(msgList);
msgRecyclerView.setAdapter(adapter);
send.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
String content = inputText.getText().toString();
if (!"".equals(content)) {
Msg msg = new Msg(content, Msg.TYPE_SENT);
msgList.add(msg);
//當(dāng)有新消息時涂炎，刷新顯示
adapter.notifyItemInserted(msgList.size()-1);
//定位到最后一行
msgRecyclerView.scrollToPosition(msgList.size()-1);
//清空輸入框的內(nèi)容
inputText.setText("");
}
}
});
}
private void initMsgs() {
Msg msg1 = new Msg("很高興認(rèn)識你", Msg.TYPE_RECEIVED);
msgList.add(msg1);
Msg msg2 = new Msg("你高興得太早了", Msg.TYPE_SENT);
msgList.add(msg2);
Msg msg3 = new Msg("你丑開", Msg.TYPE_RECEIVED);
msgList.add(msg3);
}
}
點九圖使用實例.gif
