本文實例講述了Android基于TextView實現的跑馬燈效果。分享給大家供大家參考，具體如下：
|
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
|
package sweet.venst.act;import java.io.BufferedReader;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.UnsupportedEncodingException;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.os.Parcel;import android.os.Parcelable;import android.util.AttributeSet;import android.util.DisplayMetrics;import android.view.Display;import android.view.View;import android.view.WindowManager;import android.view.View.MeasureSpec;import android.view.View.OnClickListener;import android.widget.TextView;public class AutoScrollTextView extends TextView { public final static String TAG = AutoScrollTextView.class.getSimpleName(); private float textLength = 0f;// 文本長度 private int viewWidth = 0; private int viewHight = 300; private float step = 0f;// 文字的橫坐標 private float y = 0f;// 文字的縱坐標 private float temp_view_plus_text_length = 0.0f;// 用于計算的臨時變量 private float temp_view_plus_two_text_length = 0.0f;// 用于計算的臨時變量 public boolean isStarting = false;// 是否開始滾動 private Paint paint = null;// 繪圖樣式 private String text = "";// 文本內容 public AutoScrollTextView(Context context) { super(context); } public AutoScrollTextView(Context context, AttributeSet attrs) { super(context, attrs); } public AutoScrollTextView(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // TODO Auto-generated method stub super.onMeasure(widthMeasureSpec, heightMeasureSpec); int measureWidth = measureWidth(widthMeasureSpec); int measureHight = measureHeight(heightMeasureSpec); // int measureWidth = 1024; // int measureHight = 300; viewWidth = measureWidth; viewHight = measureHight; setMeasuredDimension(viewWidth, viewHight); } private int measureWidth(int widthMeasureSpec) { int specMode = MeasureSpec.getMode(widthMeasureSpec); int specSize = MeasureSpec.getSize(widthMeasureSpec); if (specMode == MeasureSpec.UNSPECIFIED) { return viewWidth; } else { return viewWidth; } } private int measureHeight(int widthMeasureSpec) { int specMode = MeasureSpec.getMode(widthMeasureSpec); int specSize = MeasureSpec.getSize(widthMeasureSpec); if (specMode == MeasureSpec.UNSPECIFIED) { return viewHight; } else { return viewHight; } } public void setScrollText(String text) { this.text = text; inittextLength(text); // invalidate(); } public void init(Context cx) { paint = getPaint(); paint.setTextSize(40); paint.setColor(Color.WHITE); text = getText().toString(); textLength = paint.measureText(text); viewWidth = getWidth(); if (viewWidth == 0) { DisplayMetrics dm = new DisplayMetrics(); dm = cx.getApplicationContext().getResources().getDisplayMetrics(); viewWidth = dm.widthPixels; } step = textLength; temp_view_plus_text_length = viewWidth + textLength; temp_view_plus_two_text_length = viewWidth + textLength * 2; y = getTextSize() + getPaddingTop(); } private void inittextLength(String text) { textLength = paint.measureText(text); step = textLength; temp_view_plus_text_length = viewWidth + textLength; temp_view_plus_two_text_length = viewWidth + textLength * 2; } @Override public Parcelable onSaveInstanceState() { Parcelable superState = super.onSaveInstanceState(); SavedState ss = new SavedState(superState); ss.step = step; ss.isStarting = isStarting; return ss; } @Override public void onRestoreInstanceState(Parcelable state) { if (!(state instanceof SavedState)) { super.onRestoreInstanceState(state); return; } SavedState ss = (SavedState) state; super.onRestoreInstanceState(ss.getSuperState()); step = ss.step; isStarting = ss.isStarting; } public static class SavedState extends BaseSavedState { public boolean isStarting = false; public float step = 0.0f; SavedState(Parcelable superState) { super(superState); } @Override public void writeToParcel(Parcel out, int flags) { super.writeToParcel(out, flags); out.writeBooleanArray(new boolean[] { isStarting }); out.writeFloat(step); } public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { public SavedState[] newArray(int size) { return new SavedState[size]; } public SavedState createFromParcel(Parcel in) { return new SavedState(in); } }; private SavedState(Parcel in) { super(in); boolean[] b = null; in.readBooleanArray(b); if (b != null && b.length > 0) isStarting = b[0]; step = in.readFloat(); } } public void startScroll() { isStarting = true; // invalidate(); } public void stopScroll() { isStarting = false; // invalidate(); } public void onDraw(Canvas canvas) { canvas.save(); canvas.drawText(text, temp_view_plus_text_length - step, y, paint); if (!isStarting) { return; } step += 3.2;// 0.5為文字滾動速度。 if (step > temp_view_plus_two_text_length) step = textLength; canvas.restore();// invalidate(); postInvalidate(); }} |
希望本文所述對大家Android程序設計有所幫助。
